That is a shame. 90% of the criticisms I've seen of App.net were mocking it for being 'an open source twitter' and completely ignored its ambitions to encompass general social network features.
Or Pump.io, which (AFAICT) is a Facebook/Google+/Diaspora clone.
They have been starting to release the source code of the client applications they've built: https://github.com/appdotnet/