I don't know how many people have seen the icons floating around, but Ohloh.net lets you list open-source projects and say which projects you use. It also does a variety of metrics on applications it lists. It's part metrics, part "social network for developers" (apparently) and part advertising
Anyway, WarFoundry is now on Ohloh, so if you're on Ohloh then check it out and say you use it (although maybe that won't be many people yet when we've not got a first release!)