I've been enjoying this app immensely and I think it will help everyone especially when you are going into an unknown area.
Basically whenever anyone sees a cop, or knows of a speed trap, red light camera, speed camera, whatever they just click a button on the phone and put in the information.
The more people that report it the more validity that spot gets.
So when you drive by an area it will say "Police like to hide here" or "Red Light Camera in this area". You can also team it up with twitter and/or facebook.
I encourage everyone to check out the site. The more people that use it the more powerful it will become: http://www.trapster.com