Just stumbled across this and think it's a great idea:

http://bikebingle.appspot.com/

Basically, it's a place to unofficially log accidents and near miss events that happen when you're riding. I guess it's mostly for road riders who are buzzed, cut up, come across dangerous road surface, etc, but it could also be useful for logging incidents off road.

I guess the idea is that if people report incidents there is something that can be shown to authorities when trying to claim certain places need better planning?

Anyhow, seemed like a good idea and looks pretty well implemented.