Ask HN: What's the best open source social networking software?

Appleseed (I think it's called) comes to mind, every time I saw Diaspora mentioned it was cited as a more mature project with similar goals.

Define "best"?<p>elgg is a Ning alternative that's got pretty wide usage<p>status.net (formerly identi.ca) is an excellent Twitter alternative<p>Appleseed, Diaspora, and OneSocialWeb are distributed Facebook alternatives<p>crabgrass is targetted at activists<p>depending on what you're looking for, any of them might be the best

Drupal might not be what you're looking for in terms of sexiness, but it is the most mature, flexible social plumbing framework I've seen and you can do pretty much anything in it.