Consumers have enjoyed shopping via the web for over a decade, but the emergence of shopping through social media or social commerce is slowly gaining traction Instagram is one of the largest interactive photo-sharing sites that retailers, specifically apparel and accessory companies, are utilizing to sell their merchandise. Consumers are increasingly using this platform to engage, discover and get inspired; therefore, it is critical for retailers to understand how this platform influences purchase intention. This paper focuses on analyzing the impact of Instagram on consumer’s purchase intention based on an adapted model of Technology Acceptance Model and Theory of Reasoned Action. Using multi-group analysis, consumers (n=317) were divided into two groups: shopped for fashion products (including browsing, making a one-time purchase, or making repeat purchases) or not shopped using Instagram for apparel specific brands. The participants were surveyed using an online instrument with questions related to attitude, subjective norms, normative beliefs, perceived usefulness (PU), perceived ease of use (PEOU) and purchase intention. Frequency statistics were obtained for the demographic variables. Overwhelmingly (approximately 78%), respondents used Instagram daily with 82.6% following an apparel brand. 40% of the respondents had shopped previously on Instagram (i.e. browsed as well as purchased products), with 13% of these respondents spending more than $100. An exploratory factor analysis using principal component with varimax rotation and a minimum eigen value of one was used to identify the latent variables in the model: PEOU (α = 0.82); PU (α = 0.81); Normative Beliefs (α = 0.81); Attitude (α = .87); Subjective Norm (α = 0.88); Purchase Intention (α = 0.79). Results indicated that subjective norms did not influence purchase intention for both the groups indicating that consumers do not follow “groupthink” mentality while intending to purchase via Instagram. Furthermore, it was found that PEOU influence on attitude for the two groups of consumer were different, with no impact for the group who had shopped on Instagram. All the other relationships were supported in the model. These results provide both implications and limitations for retailers and academia.

The recent addition of Instagram feature, ad labels for sponsored posts, enables users to explicitly identify sponsored posts, increasing the level of transparency of posts (O’Brien, 2017). In sponsored posts in social media, followers are aware the marketing efforts that go on behind the user generated contents and message threads. Thus, the impact of postings on the followers’ behavioral response may vary depending on the levels of trust that followers have with the brand sponsored Instagram posts. In that regards, retailers implementing Instagram platform have faced creating more persuasive postings that can build the posting credibility and generate positive responses toward the brand. Grounded upon the Elaboration Likelihood Model (ELM) (Petty & Cacioppo, 1986), this study attempted to identify determinants of persuasive postings that build the message credibility of brand sponsored Instagram posts and positive responses toward the brand and to examine how the levels of trust followers have with the brand sponsored Instagram moderate the persuasion process when followers elaborate the postings. Data was collected via online survey and a total of 263 responses were determined to be usable in this study. Structural equation modeling was used to test the study hypotheses. The study results showed that post popularity and the argument quality of the post were determinants of the persuasive posting, increasing message credibility and yielding positive response towards the sponsored brand. Interestingly, post attractiveness was not a persuasive post characteristic. The results implied that post popularity and argument quality of post increased Instagram post credibility. These characteristics of posts have persuasive power to increase the post credibility, leading to a positive response toward the sponsored brand. Consumers’ levels of trust on the Instagram post sponsored brand moderated the persuasive process. The result supported that consumers with a low level of trust on the Instagram post sponsored brand carefully read a wide range of information and pay more attention to argument quality of posts, which consisted of the post content and other followers’ input regarding the product. Through the lens of Elaboration Likelihood Model, this study suggests that retailers should pay particular attention on the argument quality of a post and post popularity. The argument quality of a post is the influential factor determining persuasive and credible posts, further leveraging post credibility for consumers with a low level of trust on the sponsored post.