5. Discussion
5.1. Theoretical implications This study uses ELM theory to explore popularity cohesion, message diffusion, and persuasive messages in social networking groups. Past study on ELM focuses on changing attitudes and intentions towards information and products (Bhattacherjee & Sanford, 2006; Kim et al., 2010), but seldom on the intentions to promote social media marketing. In addition, ELM factors, in relation to social media marketing, focus on external influences (e.g., opinions of friends or online users) than on information. In this study, results show that post popularity plays an essential role in persuading users through both central and peripheral routes. Past studies about how post popularity directly influences usefulness and preferences to cause behavior intention support this finding (Sinclair et al., 2010). Post information influences center and peripheral routes at the same time, since post contains responses to content and popularity numbers. Therefore, post popularity can persuade both high elaboration and low elaboration groups. Different groups demonstrate different behavioral intentions for cohesion power and diffusion. The cohesion power of like intention affects diffusion through share intention.