Given that microblogging has been shown to play a valuable role in knowledge management within companies, it is useful to understand how it is being used in relation to OSS. This project studies tweets related to 12 open source projects and keywords, ranging from web content management systems (CMSes) to general office applications. It found considerable differences in the content and exchange of tweets, especially between specialist products such as CMSes and office suites such as OpenOffice. Tweets concerning the more specialist projects tended to provide information rather than updates on the user’s current status. We found a high proportion of event-driven traffic for some CMS projects, and a lower proportion for the office products and groups of projects.