Open source projects have an increasing importance on modern software
development. For this reason, these projects, as usual with commercial software
projects, should make use of promotion channels to communicate and establish
contact with users and contributors. In this article, we study the channels
used to promote a set of 100 popular GitHub projects. First, we reveal that
Twitter, user meetings, and blogs are the most common promotion channels used
by the studied projects. Second, we report a major difference between the
studied projects and a random sample of projects, regarding the use of the
investigated promotion channels. Third, we show the importance of a popular
news aggregation site (Hacker News) on the promotion of open source. We
conclude by presenting a set of practical recommendation to open source project
managers and leaders, regarding the promotion of their projects.