Influencer marketing is a recently emerging strategy that involves engaging people who are influential in the digital domain to share sponsored content of a brand with their followers. The purpose of this article was to review the published literature on influencer marketing, conduct a content analysis of the academic literature, and furnish a classification based on different parameters. The content analysis led to a distribution of articles as per eight different categories. This article provided the first such literature review of influencer marketing literature for the period from 2008 – 2019 to analyze and present the trends of this new marketing tactic, industries and fields involved, different platforms of social media used, key areas and methods employed by the social media influencers to connect with their followers, and spread a brand message. It was found that the major focus areas and industries utilizing social media influencers (SMIs) for brand messages and engagement of the digital consumers are lifestyles, fashion, and beauty. Empirical research was found to be predominant during the period under study. The most popular issues in the recent studies were self-presentation, para-social interactions, para-social relationships, and the credibility of the SMIs.

1. Abidin, C. (2015). Communicative intimacies: Influencers and perceived interconnectedness. Ada: A Journal of Gender, New Media & Technology, 8, 1–16. https://doi.org/10.7264/N3MW2FFG
2. Abidin, C. (2016). Visibility labour : Engaging with influencers' fashion brands and #OOTD advertorial campaigns on Instagram. Media International Australia, 161(1), 86–100. https://doi.org/10.1177/1329878x16665177
3. Agrawal, A. (2016, December 27). Why influencer marketing will explode in 2017. Forbes. https://www.forbes.com/sites/ajagrawal/2016/12/27/why-influencermarketing-will-explode-in-2017/
4. Ahmad, I. (2018). The influencer marketing revolution [Infographic]. SocialMedia Today. https://www.socialmediatoday.com/news/the-influencer-marketing-revolution infographic/517146/
5. Appelman, A., & Sundar, S. S. (2016). Measuring message credibility : Construction and validation of an exclusive scale. Journalism & Mass Communication Quarterly, 93(1), 59–79. https://doi.org/10.1177/1077699015606057
6. Araujo, T., Neijens, P., & Vliegenthart, R. (2016). Getting the word out on Twitter : The role of influentials, information brokers and strong ties in building word-of-mouth for brands. International Journal of Advertising, 36(3), 496–513. https://doi.org/10.1080/02650487.2016.1173765
7. Arora, T., Agarwal, B., & Kumar, A. (2018). A study of millennials's preferences for social media advertising in Delhi NCR. Indian Journal of Marketing, 48(10), 34–51. https://doi.org/10.17010/ijom/2018/v48/i10/132334
8. Bailey, S. (2016). Performance anxiety in media culture: The trauma of appearance and the drama of disappearance. Springer.
9. Banet-Weiser, S. (2012). AuthenticTM: The politics of ambivalence in a brand culture (Vol. 30). NYU Press.
10. Blakley, J. (2013). Brands as publishers and how it's changing marketing [Blog]. http://www.postano.com/blog/brands-as-publishersand-how-its-changing-marketing
11. Booth, N., & Matic, J. (2011). Mapping and leveraging influencers in social media to shape corporate brand perceptions. Corporate Communications: An International Journal, 16(3), 184–191. https://doi.org/10.1108/13563281111156853
12. Christodoulides, G., Jevons, C., & Bonhomme, J. (2012). Memo to marketers : Quantitative evidence for change. Journal of Advertising Research, 52(1), 53–64. https://doi.org/10.2501/jar-52-1-053-064
13. Christodoulides, G., Michaelidou, N., & Theofania Siamagka, N. (2013). A typology of internet users based on comparative affective states : Evidence from eight countries. European Journal of Marketing, 47(1/2), 153–173. https://doi.org/10.1108/03090561311285493
14. Chu, S. - C., & Kim, Y. (2011). Determinants of consumer engagement in electronic word-of-mouth (eWOM) in social networking sites. International Journal of Advertising, 30(1), 47–75. https://doi.org/10.2501/ija-30-1-047-075
15. Connors, J. (2013). The benefits of user-generated content [Blog]. http://raventools.com/blog/benefits-user-generated-content/
16. Das, K. (2009). Relationship marketing research (1994 - 2006): An academic literature review. Marketing Intelligence & Planning, 27(3), 326–363. https://doi.org/10.1108/02634500910955236
17. Daugherty, T., Eastin, M. S., & Bright, L. (2008). Exploring consumer motivations for creating user-generated content. Journal of Interactive Advertising, 8(2), 16–25. https://doi.org/10.1080/15252019.2008.10722139
18. Freberg, K., Graham, K., McGaughey, K., & Freberg, L. (2011). Who are the social media influencers? A study of public perceptions of personality. Public Relations Review, 37(1), 90–92. https://doi.org/10.1016/j.pubrev.2010.11.001
19. Gurrieri, L., & Cherrier, H. (2013). Queering beauty: Fatshionistas in the fatosphere. Qualitative Market Research : An International Journal, 16(3), 276–295. https://doi.org/10.1108/13522751311326107
20. Halvorsen, K., Hoffmann, J., Coste-Manière, I., & Stankeviciute, R. (2013). Can fashion blogs function as a marketing tool to influence consumer behavior? Evidence from Norway. Journal of Global Fashion Marketing, 4(3), 211–224. https://doi.org/10.1080/20932685.2013.790707
21. Holsti, O. R. (1969). Content analysis for the social sciences and humanities. Addison-Wesley.
22. Huang, L. - S., Chou, Y. - J., & Lin, C. - H. (2008). The influence of reading motives on the responses after reading blogs. CyberPsychology & Behavior, 11(3), 351–355. https://doi.org/10.1089/cpb.2007.0063
23. Hudson, S., Huang, L., Roth, M. S., & Madden, T. J. (2016). The influence of social media interactions on consumer–brand relationships: A three-country study of brand perceptions and marketing behaviors. International Journal of Research in Marketing, 33(1), 27–41. https://doi.org/10.1016/j.ijresmar.2015.06.004
24. Geyser, W. (2021, June 29). The state of influencer marketing 2019: Benchmark report. Influencer Marketing Hub. https://influencermarketinghub.com/influencer-marketing-2019-benchmark-report/
25. Kaplan, A. M., & Haenlein, M. (2010). Users of the world, unite! The challenges and opportunities of social media. Business Horizons, 53(1), 59–68. https://doi.org/10.1016/j.bushor.2009.09.003
26. Khamis, S., Ang, L., & Welling, R. (2017). Self-branding, 'micro-celebrity' and the rise of social media influencers. Celebrity Studies, 8(2), 191–208. https://doi.org/10.1080/19392397.2016.1218292
27. Kietzmann, J. H., Hermkens, K., McCarthy, I. P., & Silvestre, B. S. (2011). Social media? Get serious! Understanding the functional building blocks of social media. Business Horizons, 54(3), 241–251. https://doi.org/10.1016/j.bushor.2011.01.005
28. Kozinets, R. V., De Valck, K., Wojnicki, A. C., & Wilner, S. J. (2010). Networked narratives: Understanding word-of-mouth marketing in online communities. Journal of Marketing, 74(2), 71–89. https://doi.org/10.1509%2Fjm.74.2.71
29. Latane, B. (1981). The psychology of social impact. American Psychologist, 36(4), 343–356. https://doi.org/10.1037/0003-066x.36.4.343
30. Li, C. (2010). Groundswell. Winning in a world transformed by social technologies. Strategic Direction, 26(8), https://doi.org/10.1108/sd.2010.05626hae.002
31. Lithium. (2014). The power of peer reviews (White paper). http://pages.lithium.com/the-power-ofpeer-reviews
32. Lou, C., & Yuan, S. (2019). Influencer marketing: How message value and credibility affect consumer trust of branded content on social media. Journal of Interactive Advertising, 19(1), 58–73. https://doi.org/10.1080/15252019.2018.1533501
33. Marwick, A. E. (2013). Status update: Celebrity, publicity, and branding in the social media age. Yale University Press.
34. McQuarrie, E. F., Miller, J., & Phillips, B. J. (2013). The megaphone effect: Taste and audience in fashion blogging. Journal of Consumer Research, 40(1), 136–158. https://doi.org/10.1086/669042
35. Mediakix. (2019). Influencer marketing 2019 industry benchmarks. https://mediakix.com/influencer-marketing-resources/influencer-marketing-industry-statistics-survey-benchmarks/
36. Mir, I. A., & Ur Rehman, K. (2013). Factors affecting consumer attitudes and intentions toward user-generated product content on YouTube. Management & Marketing, 8(4), 637–654.
37. Ngai, E. W. (2005). Customer relationship management research (1992–2002): An academic literature review and classification. Marketing Intelligence & Planning, 23(6), 582–605. https://doi.org/10.1108/02634500510624147
38. Noyan, B. (2017, July 14). Brands are relying on 'influencer' marketing more than ever. Fortune. https://fortune.com/2017/07/13/brands-influencer-marketing-advertisement/
39. Padival, A., Michael, L. K., & Hebbar, S. (2019). Consumer perception towards social media advertisements: A study done in a semi-urban city of South India. Indian Journal of Marketing, 49(2), 38–51. https://doi.org/10.17010/ijom/2019/v49/i2/141582
40. Rickey, M. (2013, March 8). High-concept outlet from H&M influenced by fashion bloggers. The Guardian. https://www.theguardian.com/fashion/2013/mar/08/regent-street-retail-other-stories
41. Saul, H. (2016, March 27). Instafamous: Meet the social media influencers redefining celebrity. The Independent. http://www.independent.co.uk/news/people/instagrammodelnatasha-oakley-iskra-lawrence-kayla-itsines-kendalljenner-jordyn-woodsa6907551
42. Senft, T. M. (2008). Camgirls: Celebrity and community in the age of social networks (Vol. 4). Peter Lang.
43. Senft, T. M. (2013). Microcelebrity and the branded self. A Companion to New Media Dynamics, 11, 346–354.
44. Sharma, Y. (2016). Celebrity endorsements in an Indian perspective : A review. Indian Journal of Marketing, 46(11), 50–58. https://doi.org/10.17010/ijom/2016/v46/i11/104741
45. Sharma, P., Gupta, S., & Kapoor, D. (2020). Digital marketing and consumer millennials : A comparative study of men, women, and transgender consumers' buying behaviour in Punjab. Indian Journal of Marketing, 50(3), 47–57. https://doi.org/10.17010/ijom/2020/v50/i3/151029
46. Turner, G. (2010). Ordinary people and the media : The demotic turn. Sage Publications.
47. Uzunoğlu, E., & Misci Kip, S. (2014). Brand communication through digital influencers: Leveraging blogger engagement. International Journal of Information Management, 34(5), 592–602. https://doi.org/10.1016/j.ijinfomgt.2014.04.007
48. Venkataraman, N., & Raman, S. (2016). Impact of user-generated content on purchase intention for fashion products: A study on women consumers in Bangalore. Indian Journal of Marketing, 46(7), 23–35. https://doi.org/10.17010/ijom/2016/v46/i7/97125