This paper examines the claim that libre (free, open source) software involves global development. The anecdotal evidence is that developers usually work in teams including individuals residing in many different geographical areas, time zones and even continents and that, as a whole, the libre software community is also diverse in terms of national origin. However, its exact composition is difficult to capture, since there are few records of the geographical location of developers. Past studies have been based on surveying a limited (and sometimes biased) sample and extrapolating that sample to the global distribution of developers. In this paper we present an alternate approach in which databases are analyzed to create traces of information from which the geographical origin of developers can be inferred. Applying this technique to the SourceForge users database and the mailing lists archives from several large projects, we have estimated the geographical origin of more than one million individuals who are closely related to the libre software development process. The paper concludes that the result is a good proxy for the actual distribution of libre software developers working on global projects.
