Emerging trends in social media marketing: a retrospective review using data mining and bibliometric analysis

The study conducts a comprehensive retrospective analysis of the social media marketing literature along with text mining and bibliometric analysis using data obtained from the Scopus database. The analysis is conducted for the literature published during 2007–2022 using VOSviewer application and Biblioshiny. The analysis revealed the publication trend and emerging themes in the research landscape of social media marketing. This study has pointed towards important theoretical and practical implications pertaining to the social media marketing. It contributes to the understanding of social media marketing research by identifying and listing the best journal, authors, country, documents, most occurred words, social and intellectual structure, and emerging research trends. The results revealed that social media marketing research is at the focal point of the researchers throughout the word. This study found that there are lack of studies from firm perspective especially small retailers; adoption of disruptive technologies such as AI, ML and block chain and its impact need more exploration.


Introduction
The term social media came in limelight in the early 1990s, and now, it became an inseparable entity of almost every individual having an estimated 2 billion + active users globally [24].Social media is a dorm of computerbased programme that allows users to connect, create and share information and exchange views and ideas via specific virtual communities and groups (Aydin 2020).
The advancement in technology especially mobile applications and cloud-based analytics had enabled firms to offer and connect to their customers in real time.The proliferation of e-commerce web and mobile applications gives rise to the tremendous growth of social media networks and has transformed the ways of communication between business and consumers who generally shares common interests and demographics [144].Social media marketing can be regarded as a form of online marketing, and it has seen manifold growth in the recent past.The marketers are leveraging on social media platform to reach, interact, offer, and transact with their probable customers.
Many firms and brands are relying on the word-ofmouth marketing, and social media had played instrumental role in spreading word of mouth among their customers in a rapid manner that was never before.Additionally, the firms are leveraging social media network platform to expand globally [144].Social media has influenced the way consumers were searching for information, evaluating them, and making purchase decision.Moreover, social media became an inseparable integral part of businesses to sustain in this digital disruptive world.The accessibility, ease of use, realtime bound activities and global reach have made social media as a unique marketing tool.Social media enables firm to create a virtual unique platform to mark their online presence, communicate with their target customers and engage with them to increase their revenue [90].The increasing importance of social media as a marketing tool has attracted scholars especially researchers in the domain of online buying behaviour in the last decade.Therefore, existing literature on social media marketing is being continuously reviewed by scholars to understand the current trends and suggest the future directions.In recent years, researchers have studied the importance of social media in marketing from various aspects of its application.Few of the important bibliometric studies on social media marketing are mainly focussing on the social networks and platforms.Social media platforms and its role in the evolution and performance of social enterprise conducted by revealed that proper social media strategy is not only helping in increasing revenue and profitability, but also fostering confidence among the consumers.Similarly, bibliometric analysis on the pattern of co-creation , influencers , sentiments and stock market predictions and interactive digital marketing in the context of social media is conducted over the recent few years.
None of the current studies have focussed on the overall role, i.e. integrating and analysing studies focussed on behavioural intentions, impulse purchases, customer engagement, customer loyalty and recommender management of social media in the marketing landscape.The recent advancement in the mobile-based applications had forced the organizations to adopt marketing tools which are readily available to the consumers in real time [13].This study is an attempt to gather quality articles pertaining to the marketing applications of social media and analyse its effectiveness as a marketing tool.This article will help the academicians to have a holistic idea about the research trends in social media marketing that will prove conducive to design marketing strategies for industry practitioners.To the best of our knowledge, such comprehensive review of social media as a marketing tool has never been conducted.
The rest of the article is organized as follows.The next section is based on the review of literature.The research methodology adopted for this study is described in section "methods".Section "Results" is based on the data analysis and its interpretation, while limitations of this study and future research directions are presented in section "Discussion".Conclusion is made in section "Conclusions".

Review of literature
The current trends of the marketing research in the social media domain predicts that the traditional marketing is going to be entirely disrupted by the adoption of social media-based marketing.The marketing activities such as advertising, promotional programmes and branding seem to be entirely designed and applied using social media tools [144].Social media adoption is on rise because of its wide presence in the masses and its easiness of access and operate.Therefore, social media became the first choice of the marketers to promote their products and services to reach to their target audience [39].
Social media is a specialized software application that connect people in an online environment, where they can interact with each other, share contents and their feedback in the relevant groups about their experiences with a brand or organization [137].The marketers realized the importance of social media marketing and started using them as an integral part of their overall marketing strategies [89].Social media platforms enable consumers to freely interact with their fellow users on these applications and discuss openly about the advantages or disadvantages of the products [20,80].So, marketers look at social media as an opportunity to build their brand image and positively position their products in the mind of their target audience [123].The word of mouth of the consumers is also of great concern for the firms, as it may harm the brand positioning if not managed in an appropriate manner [141].
Various social media platforms such as Facebook, Twitter, Instagram, Snapchat and LinkedIn are being used by companies based on their target audience and the products they promote.As noted by [74], Snapchat is more favourite among youths, LinkedIn is more useful for reaching to mature professionals, so the marketers are selecting the platforms that suits their marketing strategy.The literatures shows that social media users are reacting more on interactive advertising rather than informational one, and it promotes interactions and cultivates the ingroup messaging among the users of a particular social media platform [11].
The synthesis of the recent literatures reveals that opinion leader is playing a crucial role around the online space, so the organizations need to select carefully their leaders who can foster confidence about the firm and positive image of the brands [25].Moreover, content is the bone of the social media marketing, and marketers need to carefully select, design and present to their markets.The emotional appeals in the messaging and overall content have been found more influential as customers has responded more often as compared to any other appeals in the social media marketing space [92,109].In a similar study, it has been found that consumers are finding live videos streaming more trustworthy and authentic as compared to pre-recorded videos [23].
Therefore, it can be concluded that social media marketing is having a greater impact on the firm, and it can bring variety of positive and negative outcomes.Studies have shown that social media marketing is having positive and substantial impact on the consumer behaviour and especially on consumer retention [52].The social media marketing efforts also play an important role in shaping the positive purchase intentions [144], brand meaning [58], brand loyalty [128], brand sustainability (X.[142,143], hotels [76], luxury brands [10], educational institutions [83], brand equity [63], positive electronic word of mouth [87], intention to engage online [127], etc.
Previous review studies on social media marketing and its effectiveness highlighted important aspects of its applications in marketing processes.Review studies have either used a specific database like web of science/Scopus [7,93] or studied a specific relationship such as brandconsumer interaction [101] in the context of social media marketing.Moreover, previous review studies focussed on specific applications such as evolving trends in Facebook marketing [94], a comprehensive comparative review of social media and social networks [144] and rise of social media in sports [78].Moreover, previous studies reviewed the influence and effectiveness of social media for a specific sector/industry such as medical [90], tourism [78], hospitality and business-to-business applications as a digital mediation [68].There is a lack of studies which has comprehensively mapped the marketing applications of social media and measured its effectiveness using bibliometric analysis.This study is an attempt to holistically examine the applications and effectiveness of social media as a marketing tool using state-of-the-art bibliometric analysis.

Methods
The development and probable future trends of a field of study can be analysed using various review techniques that can fulfil the specific objective of research.A systematic literature review (SLR) is conducted to identify, analyse, evaluate and summarize the overall findings of research in a field; it focusses on the methodological approach, theoretical framework, etc. [95].Meta-analysis is an empirical statistical technique which combines the results of multiple studies on a given problem and then estimate the overall effect and direction of the relationship (Hassan) [14,48,86,104,106].While bibliometric technique is a computer-assisted methodology that helps in measuring performance by identifying the core theme, sub-themes, prolific authors, most influential country, intellectual and social structure of the research [6,48].For current study, bibliometric research design is adopted to fulfil the objectives of the study which helps in identifying the major trends in social media marketing using network analysis techniques [135].It is one of the most used research methods which enables analysis of large volume of data to statistically estimate and visualize the research trends in a particular field of study [103].This method is widely employed by other researchers in analysis and predicting the future expansion of research in a particular domain of research [12], Hassan, [49,62,104,106].
This review is conducted in two steps; first, the descriptive analysis such as the trend of research publication, best authors and top journals of the social media research is presented and then co-citation and co-occurrence analysis are presented.For descriptive analysis, Biblioshiny applications of R is used; it allows researchers to explore their data and run descriptive analysis and present them in an intuitive tabular and graphic form [5].While for co-citation and co-occurrence analysis, VOSviewer software application is employed, it is a tool which produce output in network form-the networks are the combinations of various clusters that enables researchers to find the trending themes and sub-themes in a given area of research [126].
Scopus database is used for searching and downloading articles based on the applications of social media in marketing.The TITLE-ABS-KEY was searched using most appropriate keywords pertaining to the application of social media in marketing.The keywords such as "Social media marketing", "Social networking sites", "Social media platforms", "Facebook marketing", "Social network advertising", "Social media purchasing", and "digital marketing using social media" were searched using variety of combinations of Boolean operators (AND/OR) syntax.The inclusion of articles is based on certain criteria such as span of publication during (2007-2022), written in English language, must be either research article or reviews, and most importantly, the main theme of the literature must be on the application of social media as a marketing tool.
First search results in 2753 research articles, which are then carefully investigated for the defined inclusion criteria, book chapters, conference papers, short notes, editorial notes, etc., were removed.Literatures published in languages other than English were removed.Then, the researchers looked at tittle and abstract of each article to make sure that the central idea of research is based on the aspects of social media as a marketing tool.The final sample consists of 1232 articles, which then exported in .CSV format for further processing and analysis.
The following table is a snapshot of the data used in this bibliometric analysis.
This dataset consists of 1232 articles out of which 1183 are research articles and 83 reviews articles as presented in Table 1.There are 58,528 references cited in these studies and the average citations per documents stands at 23.23.These papers were published by 562 sources and written by 2953 authors.It is worth noting that 2994 authors have published on social media marketing, while only 173 documents are single-authored, and all other documents are multi-authored.Documents per author is 0.411, while 2.43 authors are there per document; it shows strong collaborations among authors and collaboration index stands at 2.71.

Results
The following section presents the descriptive analysis of data that is conducted using the Biblioshiny application.The .CVS file of the final data was uploaded on web service provided by Biblioshiny called bibliometrix application for further analysis.

Annual publications
The trends of publication over the years are depicted in Fig. 1; it is obvious that this area of research started in the mid of 2000s that signifies the importance of adoption of social media tools for marketing activities.Since then, there have been an exponential increase in the number of publications.From 2015 onwards, there were substantial research for understanding the effectiveness of social media as a marketing tool.As we see that there are already 65 articles published by November 2022-at the time of data extraction for this study.The trend shows that there will be continued research efforts to unveil the various aspects of social media marketing that can help marketers to understand consumer behaviour and make winning marketing strategies.
From thematic perspective, the trend can be further classified into themes which have been identified from the analysis.The early age (2000-2009) of social media marketing can be attributed to its application in advertising on social media platforms and network.This era also fuelled the development of customer groups and community where customers can interact and express their views about brands.Adoption of disruptive technologies defines trends from 2010 to 2017; during this period, smart recommendation systems, automatic feedback analysis and grievance redressal mechanisms introduced on social media.The human machine interaction signifies the trends from 2018 till date.The introduction of social robots, integration of augmented and virtual reality, realtime behavioural intelligence and super personalization can be treated as emerging themes.

Influential sources
Table 2 illustrates the most important journals publishing on the applications of social media in marketing.Top 20 journals based on total number of publications along with their total citations, and indices of h, g and m are presented.
The "Journal of Research in Interactive Marketing" is the most productive journal which has published 56 articles and been cited by 1841 times.This journal is the top-notch source in the production and dissemination of research based on interactive marketing.Few of the important themes of this journal over the years are social media influencers [131], personalization [97], adoption of disruptive technologies such as artificial intelligence and machine learning for web personalization [50] and  customer experience [4], brand-consumer interaction using social media [131].
The second influential journal publishing on social media marketing is "Journal of Business Research".This journal published 25 quality articles and been cited 2207 times.This is interesting to note that it has published articles less than half of the "Journal of Research in Interactive Marketing" but cited more often than that.This journal has contributed in the comprehension of the phenomenon of social media marketing by publishing on important aspects such as fake news and social media marketing [30], social media and brand equity [145], customer engagement via social media [40] and use of social media for B2B marketing [122].
Sustainability (Switzerland) is the third most important source that publishes on social media marketing.It has published 20 articles and attracted only 197 citations since its starting publications.This journal is publishing important aspects of social media-based marketing such as implementation of green marketing using social media [85], impact of social media on environmental sustainability [27], digital co-creation [22] and role of social media in organizational sustainability [138].
The other journals in the list have also contributed immensely to the growth of social media marketing research and its implications for the businesses.

Most prolific authors
The most prolific authors researching and publishing on social media marketing are presented in Table 3; this selection is based on the number of papers published by an author over the period, and their total citations and h-index are also presented for a better comprehension.The first author in the list is Kumar V; he has published six quality articles on the applications of social media tools in marketing.Some of the most influential articles published are "Engaging luxury brand consumers on social media", "Synergistic effects of social media and traditional marketing on brand sales: capturing the time-varying effects", "Creating a measurable social media marketing strategy: Increasing the value and ROI of intangibles and tangibles for Hokey Pokey", "Increasing the ROI of social media marketing" and "An evolutionary road map to winning with social media marketing".All the above-mentioned articles are focussing on specific marketing applications of social media.The second author in the list is Dwivedi YK with four papers and 718 citations and with an h-index of 4. The important articles published are "Examining the impact of social commerce dimensions on customers' value cocreation: The mediating effect of social trust", "Measuring social media influencer index-insights from Facebook, Twitter, and Instagram", and "Social media marketing: Comparative

Table 2 Top 20 Journals
"h-index is defined as the maximum value of h such that the given author/journal has published h papers that have each been cited at least h times; g-index is calculated based on the distribution of citations received by a given researcher's publications, such that given a set of articles ranked in decreasing order of the number of citations that they received; m-index is defined as h/n, where n is the number of years since the first published paper of the scientist; also called m-quotient.TC stands for total citations, NP: Number of papers; PY_Start: Production year started" (

Most important documents
Table 4 presents the top research papers published on the application of social media in marketing.These papers are listed based on their number of citations it has attracted over the years.The top document is written by Kozinets RV and focussed on the importance of the virtual online crowd, where consumers come together to discuss, share their opinion that results in collective innovation.Moreover, this paper emphasizes on the proliferation of networking technology that made online collaboration easy to access and interact; technologies help innovation to take new heights that ultimately impact the consumption patterns of the consumers.This paper has been cited 1077 times with an annual average of 83.
The second influential document found in this dataset is about social media marketing that was published in 2012 and cited 996 times by then.This paper has analysed the importance of social media in marketing from important aspects such as self-expression, socializing, brand interactions and the social communities that have substantial influence on the consumer purchasing intentions and purchasing behaviour.In addition, this paper also touches the importance of the impulsive buying activities on social media platforms; consumers are getting intimated with intuitive advertisements on social media platforms and landing to the e-commerce websites that instigate impulse shopping urges [13].
The paper published by Journal of Business Research and written by Kim AJ stands third in the list of most influential articles.This paper has investigated the role of social media in enhancing the customer equity with a special focus on luxury fashion brands.This paper was published in 2012 and attracted 904 citations by then.This paper explored the influence of social media marketing activities on customer perceived value, brand equity and customer equity.The findings favour the proposition that customer equity is highly enhanced by social media marketing activities.
The other documents in the list have also been contributed to the understanding and expansion of the area of social media marketing research.Few of the important themes discussed in these papers are measuring ROI of social media, creative social media marketing activities, online reviews, user-generated contents, influencer marketing, etc.

Most productive countries
The countries contributed most to the research stream of social media marketing are illustrated in Table 5.The countries are selected based on the number of citations of their articles.The greatest number of research articles are contributed by USA; it has produced 222 research papers, and these papers have been cited 7065 times with an average article citation of 31.82.It indicates the adoption of social media as a marketing tool in the USA; the researchers are studying the underlying factors which are crucial to understand consumer behaviour in the space of social media marketing activities.
Moreover, it also indicates that countries having better networking facilities and high bandwidth internet can exploit the advantages of social media marketing more efficiently than the countries not at par in terms of internet and networking facilities.The other two important countries are UK and China with 3195 and 1674 citations, respectively.It can be noticed that there is huge disparity among top 3 countries in terms of publications and number of times it had been cited.Nevertheless, the trend is showing that the proliferation of internet technology and availability of high-quality internet will boost the adoption of social media among users and social media marketing among the business firms.

Citation analysis of the documents
Citation analysis is the method of assessing the quality and impact of an organization, author, source, etc., derived from the quantitative analysis of the citations to references [103].VOSviewer application is employed for this purpose, and minimum number of citations of a document was kept 10.The network thus obtained contains four clusters based on the grouping of a specific theme in social media marketing (Fig. 2).
The largest cluster (red) of the network is made up of 134 documents and consists of large nodes which specifies the greater number of citations these documents received over the time.The important aspects of social media marketing in this cluster are mainly focussed on the information processing that can be further used to make strategies pertaining to the social media consumers [88]; analysis of the online conversation among users is of enormous importance because it is crucial in affecting the consumer behaviour either positively or negatively about the firm and its products [2,31,66].B2B semantics is useful for understanding the deep inside thoughts of the firms and their leaders that ultimately shapes their behaviour [34,128].In addition, the application of big data analytics tools is for processing and analysing the large amount of data to learn pattern of consumer interaction and activities on the social media network platforms [55,74,110].Another important consideration in this cluster is about the use of sentiment analysis and opinion mining for managing the expectations of the consumers and offering them most customized products as per their unique needs.The green cluster, second major in the network, is made of 93 documents.This cluster of this citation network is found to accumulate documents that addressed the research concerns of consumer behaviour from the perspective of social media marketing.The role of social media-based marketing in shaping the consumer intention to purchase [37,84,123], the impact of personalized content and its impact on consumer behaviour [19,140], consumer social media participation and its impact on overall profitability of the firm [26,29], persuasive advertisement and its impact on customer engagement [42,67,113].
Third cluster (blue) consists of 69 documents on various important aspects of the social media marketing from the perspective of customer engagement.The documents which have formed the basis of this cluster are essentially addressing the concepts of mutual sustainable relationship between customers and e-retailers are perceived value that a customer assessed about the product of services that meets their unique expectations [44,82].The service quality on the shopping websites and applications is crucial to persuade customers to revisit and explore which ultimately increase the chances of customer engagement, while poor service quality demoralizes customers and decreases the level of engagement significantly [34,133,134].In addition, customer experience that includes important factors such as personalization, tailoring of offers to match unique expectation of customers, are substantial in the course of customer engagement [116,123].Customer engagement cannot be achieved if customer satisfaction is not central to a firm, and it must be the prime focus, and marketers needs to make all possible efforts to not only satisfy, but also delight their target customers [33,41,43].

Keyword co-occurrence analysis
The keyword co-occurrence analysis can be referred to as a method of analysing the similarities and proximity between knowledge structure that is based on the semantics of the words which are closely related but not exactly the same [13].For this analysis, VOSviewer software is employed, and it is among the best tools for scientific data visualization and mapping of co-occurrence of similar keywords to discover the emerging trends in a specific area of research [12].
The criteria for a keyword to be included in the network was that a keyword must have a frequency of at least 15.The frequency of occurrence is set as 15, to make sure the inclusion of significant keywords that can help in visualizing the scientific landscape.The network thus obtained is based on 235 keywords out of 4061 and presented in Fig. 3.This network is based on three specific clusters having combined keywords pertaining to a specific aspect of the social media marketing.
The largest cluster of the network is represented by red colour and consists of 110 keywords.This cluster is made up of keywords that signifies the importance of technology in social media marketing and social networks.This cluster also explains the importance and adoption of disruptive technologies in the application of social media in marketing activities.The role of artificial intelligence [57,73,130], machine learning [72,74,109], learning algorithms [9,31,121], sentiment analysis [109], learning systems [9,130], CRM tools [29,125], customer interactions [42,117], customer reviews [116,124] and recommender applications [98,112] has been studied over the period to implement them efficiently for better business outcome.Moreover, this cluster is having important implications for the designers, developers, and implementers of the social media marketing campaigns; it is crucial for the organizations to first collect the large amount of data resulting from the customer exploration of their web portals and process them to learn the trends and expectations of the consumers.This comprehension can further be used to design marketing efforts across the channels to reach to target markets, motivate them to interact over social media and engage into activities that can lead to profitable business transactions.
The second largest cluster (green) consists of 64 keywords; careful analysis of this cluster reveals that this cluster has combined the keyword which is centred around consumer behaviour on social media platforms.The important perspectives of consumer behaviour that can be visualized in this cluster are perceived value [79,129], purchase intentions [52,99,100], brand value [17,115], brand loyalty [10,133], brand image [107,114], ethics [28,91], green behaviour [10,130], sustainability aspects [99,130], millennials [10,34,35], generation [39,118], and customer engagement [99,107,140].Therefore, it is quite evident that social media tools are being used in almost all facets of consumer behaviour; the above studies also concluded that the use of social media marketing tools has a positive and substantial impact on consumer behaviour.

Fig. 3 Keywords co-occurrence analysis
The third and last cluster (blue) of this network is made of 51 items.This cluster has accumulated keywords which are focussed on the human aspects of social media marketing.As it is obvious from the network that the largest node in this cluster is "human" and "humans", which specifies the interaction of machine, i.e. computers with human [36,58,139].The human computer interface is a trending research stream in social media marketing, where efforts are made to understand the best practices to interact with computers in a more efficient manner [129,136].The another important concept in this cluster is about psychology which is quite important for the marketers to understand the cognitive process of consumer when presented with marketing stimuli using social media marketing tools [59,117].Few other keywords which dominated this cluster are health education and monitoring health using social media applications [28], young adults [81,130], selection of advertising topics [1, 51], etc.

Trends in social media marketing
The network analysis helps in the identifications of emerging trends in the research of social media marketing.The social media networks allow users to interact and share their thoughts and experience with a brand which in turn helps in viral marketing [120].The possibility of sharing podcast and video contents has fuelled the interactivity among users [15].The reviews and feedback are of enormous importance for the marketers to listen the voice of the customers and adapt accordingly [54].
One of the major trends is about real-time personalization on the social networks; the recommender system is recommending most sought-after products to the customer in real-time web exploration.The personalization in real time is achieved using technologies such as artificial intelligence, machine learning and predictive analytics that helps in gaining deeper insights into behavioural intentions [3,96].
The introduction of augmented reality and virtual reality is another latest trend that have revolutionized the way marketing was being carried out using social media networks.The augmented reality has enabled the customers to virtually look at desired aspects such as suitability, colour combinations, fittings and virtual trials [39].It gives consumers the confidence to immediately decide to purchase and quick gratifications [119].The impulse purchasing mechanism is also trending on social media platforms; the firms are appropriately designing and putting across their offerings that creates urge to buy impulsively [61].
Influencer marketing and brand endorsement are not a new trend, but it is one of the major trends that is going to stay for a while.The brands are associating with influencers who have huge followers and witnessed better results as good as running paid advertisement campaigns [39].
Live streaming has been adopted by various firms to reach to specific segments of their target markets using webinar or a platform showcase [18].It gives them opportunity to socialize and interact with prospective customers and engage with them through Q & A sessions or collaborative contents [18].

Themes and sub-themes in social media marketing
The detailed analysis of the networks of citations and keyword co-occurrence analysis helps in identifying themes and sub-themes which are emerged from the clusters of the network.Table 6 is representing the main themes and sub-themes along with related studies.

Discussion
Each research study is having certain limitations and so as this one.One of the major limitations is about citation bases analysis; the selection of articles is based on the number of citations it has received.There might be important studies on social media that may have not been included in the analysis because it did not receive many citations.Moreover, we selected research literature written in English language and either article or review paper; there might be quality articles that left behind.
As far as future direction of research is concerned, it is obvious that social media marketing is evolving at ever high pace and there is a need for deeper investigation into this phenomenon.Careful investigation of the networks unveils important areas of future research expansion.First, the adoption of social media among consumers, what are the factors that hinders the usage of social media and technological barriers that restricts the customers to use social media are needed to be explored further.Studies have shown that one of biggest barrier in the adoption of social networks and platforms is the availability of high speed affordable internet networks [132].Therefore, TAM model needed to be revisited from social media perspective, and additional components can be added to understand the adoption of technology and social media applications.A versatile model could be developed that can be used in variety of technology adoption scenarios and can be generalized in various environments.There is a need of study to understand the firm capabilities required and preparedness to adopt social media marketing practices.
The second important area of research is from the firm perspective; still it is not very much clear that how disruptive digital transformation and technologies such as artificial intelligence, Internet of Things, machine learning, deep learning, etc., can be implemented to get maximum ROI and that can persuade consumers to transact with them.Studies have focussed on artificial intelligence applications such as recommendation system which is positively influencing the consumer behaviour especially purchase intention [10,53].The future studies can help in building a comprehensive model that could be used by the firm to evaluate their investment, ROI, perceived value to customer and overall consumer behaviour.
Thirdly, there is a lack of study on the influence of social media marketing on small retail firms.More studies are warranted to seek clarity about the effectiveness of social media as a marketing tool for smaller firm, which social media tool and tactics will be more advantageous for these firms.Researchers are also encouraged to empirically explore the small retailer's perspective of adopting social media tools for their marketing activities.There shall be a mechanism to gauge the outcome of social media marketing on their brand awareness, customer growth, sales, and overall profitability of smaller retailers.
Fourth important area of research could be the deliberations of the social content.Content is the core of social media platforms; studies have shown that consumers tend to get attracted and spend more time on the social network where they can create their own content in an easy manner.Content is also crucial in terms of its suitability across platforms and ethical implications.
Therefore, researchers can study and analyse the most appropriate content across the social media platforms, devices and for a specific business.Researchers can explore the critical aspects of social content such as most suitable content for C2C interaction, firm reaction on a specific customer content, content to combat competitions, etc.
Fifth area of future research could be the monitoring of social media, how a firm shall record and acknowledge complaints of the customers.The sub-themes in monitoring can be to find out the best listening mechanisms of consumer activities that can be further analysed using predictive analysis mechanism to develop strategies to engage customers in the way they might be looking for.Another investigation can be done to seek clarity about the mechanism of watching and listening customers, i.e. whether there should be a fully automated process or hybrid one.This is important for the firms to understand the probable capital investment in the implementation of monitoring and responding process.This subject can be further investigated from the CRM perspective.Research can be extended to understand the role of various social media platforms on customer engagement, and what should be the capability of the CRM to exploit maximum from customer created content.

Conclusions
Bibliometric analysis is performed to have a comprehensive understanding of the applications of social media for marketing activities.The aim of the research was to investigate the research trends and emerging themes using the Scopus database.The findings of the research reveal the most important journals, authors, documents, and their intellectual structure.Moreover, it is found that research in the application of social media as a marketing tool is growing at an ever-increasing rate.Scholars around the world are collaborating with each other to comprehend the phenomenon and suggest strategies that can help firms to exploit the power of social media platforms in their marketing tactics.The outcomes of the research shown that there are certain areas of social media marketing landscape which need more scholarly attention; current literature has not considered these essential factors in detail.The findings suggest that current extant literature can be expanded by appending research in the areas such as modelling social media marketing ROI, social content strategies, monitoring and responding social media activities, social media strategies for smaller retailers, etc.This study has enumerated important implications along with the analysis for the businesses.The outcomes would also be helpful for social media enthusiasts and prospective social media marketing researchers.

Fig. 1
Fig. 1 Annual publication trends in applications of social media in marketing

Fig. 2
Fig. 2 Citation analysis of documents

Table 1
Data characteristics [104,106]04,106]Social media marketing: Comparative effect of advertisement sources", "social media in marketing: A review and analysis of the existing literature".Rana NP has authored various articles in collaboration with Dwivedi YK as well.

Table 3
Top 20 authors

Table 5
Top 20 countries

Table 6
Themes and sub-themes in social media marketing