Context: the ability to follow other users and projects on GitHub has introduced a new layer of open source software development participants who observe but do not contribute to projects. It has not been fully explored how following others influences the actions of GitHub users. Objective: this paper studies the motivation behind following (or not following) others and the influence of popular users on their followers.Method: a mixed methods research approach was used including a survey of 800 GitHub users to uncover the reasons for following on GitHub and a complementary quantitative analysis of the activity of GitHub users to examine influence. Our quantitative analysis studied 199 popular (most followed) users and their followers. Results:we found that popular users do influence their followers by guiding them to new projects. As a user’s popularity increases, so does their rate of influence, yet the same is not true for a popular user’s rate of contribution. Conclusions: these results indicate that a new type of leadership is emerging through GitHub’s following feature and popularity can be more important than contribution in influencing others. We discuss implications of popularity and influence and their impact on social structure and leadership on OSS projects. © 2015 Elsevier B.V. All rights reserved.