As useful tools in delivering information services, social media could create a wide range of opportunities and reduce communication costs significantly. The present study set out to initially identify the potential roles of social media in information services using a systematic review procedure. Using the meta-synthesis method, the identified roles were organized in a conceptual model and then prioritized through Shannon’s entropy technique. The results showed that the operational, financial, strategic, user-related, and informing roles ranked first to fifth, respectively. In the last step, the results of a survey of 30 experts active in online information services were analyzed using the weighted average method to be compared with the findings of the systematic review. The order of prioritization of the roles and indicators from the experts’ point of view showed financial, user-related, strategic, operational, and informing roles, respectively. The prioritization of roles in Shannon’s entropy method was similar to the results from the perspective of experts in terms of strategic and informing roles. However, experts have come to understand more about financial and user-related roles for social media. The only factor that had the greatest difference in ranks between Shannon’s entropy method and experts’ opinions survey was the operational role, which ranked first in Shannon’s entropy method and fourth in expert scrutiny. The present study is one of the first attempts to identify the possible roles of social media in information services that can be considered a pioneering research by related researchers.