The original DiaryCollective? and a WebLog-style community forum and news site for free software developers. Also a testbed for the Advogato TrustMetric, which uses a network flow model to rate the community's "trust" of a user based on other users' certifications.
Another important part of Advogato that is not immediately noticeable to newcomers is the use of diary entries not just for personal monologue but also for dialogue. Many people have begun using their own diaries to respond to frontpage articles and to other users' diary entries.
This is similar to some of the uses people have found for personal WikiWikiWeb pages.
For the "recent changes" of the diary entries, check out Advogato:recentlog.html.
There is a good overview Salon article on Advogato here, http://archive.salon.com/tech/feature/2000/07/18/advogato/index.html.
There's been a flurry of articles lately on Advogato about TrustMetrics and whatnot. I've been thinking that a good dose of SoftSecurity would be refreshing. Something to point out that trust metrics are cool, but they're no silver bullet. Think carefully before choosing a trust metric; your "need" for HardSecurity might really belie a deeper problem.
AdvoGato is always complaining about how people aren't rating intelligently, but that's because quantizing feeling is difficult: RatingIsHard?. So people just make simplistic decisions. You'll find the same sort of thing on kuro5hin where people try making rules so they rate consistently or just give up and claim they rate based on how they feel. Making constant social decisions like this is taxing, in the same way that picking between different shades of white paint is taxing. Besides, the most entertaining thing to do with TrustMetrics is to mess with them, ala the blackbox tit-for-tat rater, or "esr". See LimitTemptation. One defense is to make trust a DynamicValue.
For some internal discussion on Advogato's trust metric, see Advogato:article/599.html and Advogato:article/609.html . Most of the discussion I found was centred around the perception that the awarded levels do not match the definitions of those levels, which are based around developer skill and importance. Instead of merely following the decreed guidelines, "certifiers" are strongly influenced by social factors. Also, there was a feeling that the level thresholds may need to be adjusted, or more levels introduced.
2004-07-03: After a month-long server outage, Advogato is back up and is appealing to the community for financial and/or technical help running the site. See Advogato:article/777.html for details.