Navigating the Future of Influencer Advertising: Consolidating What Is Known and Identifying New Research Directions

Social media influencers (hereafter referred to as influencers) have come to be central actors in an increasingly interconnected digital and social advertising system. In the following introduction, we briefly outline where the academic understanding of influencers currently stands, how the articles included in this issue section add to this knowledge, and where we believe opportunities for further contributions exist.

Table 1 summarizes this discussion by sorting it into four key interconnected parts of the influencer advertising ecosystem: advertisers, influencers, consumers, and content. Due to the brevity of this editorial, we include only a limited number of citations and direct readers to excellent recent literature reviews (e.g., Hudders et al. 2021; Ye et al. 2021) for richer discussions of the literature.

Table 1. The past, present, and future of influencer advertising.

Perspective	What Is Known	What This Special Section Adds	What Remains to Be Discovered
Advertiser	Influencers are generally effective advertisers. Consumers react better to the same content from influencers than from brands (Lou et al. 2019). Consumers react better to influencers than to celebrities (Schouten et al. 2020). Artificial intelligence influencers can be as effective as humans.	Influencers can produce a variety of different content types as part of a campaign (Scholz 2021). Advertisers can collaborate with influencers in a multitude of different ways (Rundin and Colliander 2021). Micro-influencers are more effective at advertising hedonic products than utilitarian products (Park et al. 2021). Influencers are effective at advertising social causes (Yang et al. 2021).	How can influencer campaigns be effectively integrated with other types of advertising? How can advertisers predict which influencers are best for their campaigns? What factors moderate the effectiveness of influencer advertising? How can fraudulent or fake influencers be identified? Which community-centric key performance indicators best capture influencer performance? What communication objectives (e.g., awareness, purchase) are influencers most suited to achieve? What mechanisms can influence this?
Influencer	Influencers are dependent on consumers following them. Influencer–product fit increases persuasiveness. Attractiveness, credibility, authenticity, and trustworthiness boost influencer persuasiveness. Perceived motives affect persuasiveness and can be shaped by influencers. Influencer interactivity boosts authenticity and attachment, increasing persuasiveness.	Being active across platforms is necessary for influencers to become successful (Brooks et al. 2021). Influencers’ success likely depends on the roles they take when collaborating with brands (Rundin and Colliander 2021). Micro-influence success is driven by the perceived authenticity of the influencer (Park et al. 2021).	How can influencers choose the right brands with which to work? And the right number and mix of them? How do influencers maintain celebrity capital (i.e., later stages of celebrification or the celebrity life cycle)? How might growing from a micro- to macro- influencer affect how an influencer operates? What influencer roles create the most value for consumers and advertisers? How do long-term commitments and/or number of collaborations affect influencer persuasiveness? How does wear-out impact influencers?
Consumer	Consumers self-select which influencers they follow, typically motivated by authenticity, consumerism, creative inspiration, and envy (Lee et al. 2021). Consumers respond more positively to influencers who are similar to them or who they aspire to be like. Activation of persuasion knowledge often has minimal impact on consumer response to influencers, and disclosure can lead to positive effects (Lou 2021); these effects can be enhanced by justification. Consumers’ parasocial relationships with influencers mute the negative effect of persuasion knowledge. A strong parasocial relationship makes a consumer open to being advertised a wider array of products.	Consumers and influencers can be similar along multiple different dimensions, suggesting that identification in an influencer context is complex (Scholz 2021). Consumers derive value from influencer content in six different ways (Scholz 2021).	How are influencers consumed in nonbeauty and nonfashion contexts? When do consumers view an influencer as a consumer? A celebrity? An entrepreneur? A brand? And how does this affect consumer response to the influencer? How is an influencer’s success affected by their choice of social media (e.g., YouTube versus Instagram) and/or by specific content types (e.g., Instagram feed versus story versus IGTV)? How is response to an influencer affected by the type of similarity a consumer shares with an influencer?
Content	Informativeness and entertainment make influencer content more appealing. Content that is more narrative and higher in social presence/affective can mute persuasion knowledge activation (Lou 2021). Hard-sell appeals are more effective than soft-sell appeals. Disclosures are generally effective in making consumers aware influencers are advertising (see Eisend et al.’s 2020 meta-analysis). More transparent disclosures receive better reactions. More overt disclosures are more effective.	Micro-influencer content should focus on hedonic rather than utilitarian appeals (Park et al 2021). Content can be adapted to the six different ways in which consumers derive value from influencers (Scholz 2021). Content needs to be adapted to enable effective use across platforms (Brooks et al. 2021).	To what extent does the quality (e.g., aesthetics or creativity) of influencer content affect consumer response? How is the trade-off between authenticity and professionalism navigated by influencers and reacted to by consumers? How are advertising appeals adapted to an influencer environment? Do other new or hybrid appeals exist (e.g., proactive disclosure; Lou 2021)?

What Is Known about Influencer Advertising?

Influencer advertising (also referred to as influencer marketing) has shown tremendous growth in the past decade. There is no question that the influencer industry is large, here to stay, and continuing to grow (Campbell and Farrell 2020). The existing academic literature has given us the following insights.

Influencers Are an Effective—and Major—Advertising Form

Both academic research and results from industry make it clear that influencers can be an effective form of advertising. In fact, research shows that content by influencers can be as effective as or more effective than advertising by either brands or celebrities. In addition, influencer persuasiveness is not limited to humans; artificial intelligence influencers can also be effective.

Insights on Endorsements Generally Apply to Influencers

Much of the endorsement literature applies to influencers. Consumers follow influencers for various reasons, including aspiration, envy, entertainment, and intrigue. Perceptions of attractiveness, authenticity, credibility, and trustworthiness increase influencer persuasiveness. So too does a strong fit between an influencer and what is endorsed.

Consumer–Influencer Connection Drives Effectiveness

Still, influencers represent a unique blend of paid endorsement being injected into what otherwise might be construed as word of mouth, a blend which seems to drive their success. Research shows that consumers’ sense of personal connection with (known as parasocial relationship) and similarity to an influencer enhances influencer effectiveness. So does increased interaction and engagement between an influencer and the consumers that follow them.

Disclosures on Influencer Content Work As Expected . . .

Eisend et al.’s (2020) meta-analysis of the numerous studies on this topic confirms that a disclosure on influencer content generally makes consumers more aware that an influencer is paid, increases persuasion knowledge activation, and reduces persuasion. Likewise, clearer and more overt disclosures are more effective in triggering these effects than disclosures that are less transparent.

. . . Yet Consumer–Influencer Connection Mutes the Effectiveness of Disclosures

Still, perceiving a strong relationship or connection with an influencer is shown to make consumers less concerned about an influencer’s commercial interests. In fact, influencers who share that they are paid but provide justification for accepting payment can be seen more positively (e.g., Lou 2021). Using narratives, being more affective, and having a stronger social presence all decrease persuasion knowledge activation. Consumers also respond to influencers based on their inferred motives, but those motives can be shaped by the influencers themselves.

What Insights Does This Special Section Add?

This special section set out to develop knowledge of how advertisers can derive benefit from influencers. Answering calls for a more diverse and contemporary development of advertising theory (Dahlen and Rosengren 2016), it sought contributions that add novel understanding of the mechanisms through which influencer advertising works and how advertisers can best leverage influencers. The five articles included add the following to the literature.

Advertisers Collaborate with Influencers in Multiple Different Ways

Rundin and Colliander (2021) show that influencers take on a variety of different roles in their collaborations with advertisers and brands, many of which are much deeper relationships than mere endorsement. Their article provides both a “menu” of roles for advertisers to consider when hiring influencers as well as a typology for researchers to use when analyzing influencer campaigns.

Influencers Create More Than Sales

Yang et al.’s (2021) investigation into content related to the Black Lives Matter movement shows that influencers are more likely than brands to facilitate positive engagement around a cause, especially when the fit between influencer and cause is high. It also highlights how influencers can mitigate consumer skepticism around cause-related messaging. This suggests that advertisers should not restrict their influencer collaborations to efforts focused on sales and that researchers should extend their investigations to examine non-sales-related outcomes.

Influencers Act Differently Than Celebrities Because Their Status Is Acquired Differently

Brooks et al. (2021) outline a distinct process by which influencers acquire celebrity capital within an interconnected social media advertising system. The need for influencers to maintain celebrity capital puts power in the hands of their consumer following and advertisers. This dependency makes influencers naturally prone to advertise more collaboratively than traditional celebrities. It also complements Rundin and Colliander’s (2021) finding that influencers often act as much more than mere endorsers.

Consumers Consume Influencer Content in Several Different Ways

Scholz (2021) identifies six ways in which influencer advertising is consumed. His insights provide influencers and advertisers with a useful tool for developing and assessing campaigns (e.g., “Are our ads addressing all six consumption modes?”). For researchers, Scholz’s findings also highlight that consumer–influencer similarity operates in a more nuanced manner than traditionally thought.

Influencers Advertise “with” Consumers, Not “to” Consumers

Scholz’s (2021) article also highlights that influencer effectiveness is based on more than source effects. Both Scholz’s article and Brooks et al.’s (2021) article show that influencer persuasion depends on intrinsic linkages between influencers and their audiences, as well as the content being produced and the products and/or brands advertised in that content. Understanding of ads created by influencers is thus highly contextual.

Micro-Influencer Effectiveness Is Driven by Authenticity

Park et al. (2021) show that increased authenticity is what makes endorsements from micro-influencers more effective than those of mega-influencers. Their article also shows that this effect occurs only for micro-influencers when their advertising involves hedonic—and not utilitarian—products and appeals.

Where to Next?

We call for research to continue to explore the role influencers have in our increasingly interconnected digital and social advertising system, characterized by the continuous flow of new formats, new consumer behaviors, and new effects (Dahlen and Rosengren 2016). In addition to future research needs identified in each article, Table 1 summarizes specific areas we believe are worth exploring. However, we also see three broader themes evident across future research efforts.

Influencer Advertising Deserves Influencer-Specific Theorizing

A common theme across the Scholz (2021), Brooks et al. (2021), and Rundin and Colliander (2021) articles is that using traditional advertising theories to understand influencer marketing runs the risk of missing what is unique about the phenomenon. This point is also made by Lou (2021). The relationships between advertisers, influencers, consumers, and content are more dynamic and synergetic than that of placing an ad in a specific medium or hiring a celebrity to promote a product. This special issue highlights the need to refresh and reground our understanding of influencers in the influencer phenomenon rather than solely draw on theorizing from celebrity endorsement and source effects. For example, rather than studying how different disclosures (which are already required in most countries) may or may not affect persuasion, we might consider how audience interactivity impacts persuasion.

The Complexity of Influencer Advertising Necessitates Different Research Designs

Given the dynamic and synergetic nature of the influencer advertising ecosystem, we need to design empirical studies that account for the interrelationships between advertisers, influencers, consumers, and content. A single exposure to an ad from an unknown influencer is unlikely to replicate the effect of seeing an ad from an influencer a consumer has followed and trusted for years. Capturing such nuance and context will likely require industry collaborations, longitudinal data, and/or field experiments involving actual influencers, as well a range of different methods.

Influencer Advertising Must Explore Issues of Importance to Advertisers

Our review of the literature and reading of all the contributions to the special issue highlights a lack of research examining how advertisers can best work with influencers and how influencers can be integrated into other advertising efforts. Further research that goes beyond studying the effects of influencers as mere spokespersons (Rundin and Colliander 2021) or investigates the effect of cross-platform appeals (Brooks et al 2021) is needed. Research that looks beyond the hedonic contexts of beauty and fashion (Park et al. 2021) or examines cause-related appeals (Yang et al. 2021) would also be valuable. Uncertainty also exists related to selecting and evaluating influencers, detecting fraud in the industry, and choosing success metrics.

Acknowledgments

We are grateful to everyone who contributed to make this special issue possible. We thank Shelly Rodgers, editor in chief, for trusting us to edit this issue and offering invaluable guidance and support throughout the process. We thank all the authors who submitted more papers than we could have ever expected—68 in total!—which necessitated tough decisions to fill the issue’s five slots. Finally, we deeply thank the reviewers who shared their expertise.

Additional information

Notes on contributors

Sara Rosengren

Sara Rosengren (PhD, Stockholm School of Economics) is a professor, Center for Retailing, Stockholm School of Economics.

Colin Campbell

Colin Campbell (PhD, Simon Fraser University) is an assistant professor, Department of Marketing, School of Business, University of San Diego.