The Document Foundation has been posting regular and extremely thorough analysis/graphs of their growing base of contributors to the open-source LibreOffice project:

http://blog.documentfoundation.org/2012/02/02/fosdem-preview/

The Document Foundation was announced on September 28, 2010. So far, it has been an unbelievable ride, especially under the development point of view. Our core development team has managed to attract close to 400 new developers, and has achieved a large number of the ambitious goals set on that date. We still have quite a long way to go, but LibreOffice 3.5 – due next week – will be the very first release showing TDF “development directions” not only to geeks but also to end users: a leaner and cleaner office suite, packed with new features.

I wish it were as easy to enumerate the contributions of our community, but many happen in person at public events. RJ Steinert and I (and others) have been brainstorming and testing new ways of representing the broad contributor base of the PLOTS community:

• "github graphs" - https://github.com/jywarren/plots/issues/43
  • http://publiclaboratory.org/wiki/github-graphs
• https://github.com/jywarren/plots/issues/77

In that last one, RJ cites a Mozilla interface design which tries to highlight when people stop contributing, red-flagging them as possibly frustrated or starting to lose interest. Read more: http://eaves.ca/2011/04/07/developing-community-management-metrics-and-tools-for-mozilla/

Anyways I think we should have a larger public discussion of some of these strategies and would welcome input from folks interested. Maybe even a sub-mailing-list is in order...