BuddyPress.org

The approach to take in a plugin is to hook into the various WP and BP actions and then reward achievements as and when appropriate. You need to record in the database which achievements have been obtained. And write the administration and user interfaces for BuddyPress as a custom component.

I am myself working on an achievements plugin. I had hoped to release a test version today but I can’t promise that, it’s looking unlikely. But we shall see..