Advogato
Advogato is a social website for the free software community that was founded by Levien in November 1999, who had two principal motivations: first, to test his ideas of attack-resistant trust metrics, and secondly, to provide a development-focused forum for the free software community that was free of the kind of commercial motivations of such sites as Sourceforge.
The site has been successful from the point of view of the first criterion, surviving many attacks aimed at subverting the attack metric, made both by developers trying out attacks, and by spammers. The site has needed only relatively minor changes to cope with these. The site's trust metric provides, alongside Epinions, one of the two most important datasets used in empirical analysis of trust metrics and reputation systems. Levien observed that Google's PageRank algorithm can be understood to be an attack resistant trust metric rather similar to that behind Advogato.
The site has had a more rocky road as a forum for free software developers, and currently hosts less discussion than at its peak as developers have moved from forums to weblogs. Due to this, Advogato has added a syndication feature which includes the weblogs of its current certified developer base. It remains one of the earlier networking sites, and is still a place for active discussion on development of free software.
Read more about this topic: Raph Levien