The Weewar Players Association (WWPA) by Pistos maintains and publicizes a “list of players who adhere to some modest guidelines on fair and honorable play”. You can sign up and certify other players based on your experience playing with them. Really clever and already really popular!
There are more projects like this in the works and we are happy to introduce them when they are ready. If you want feedback or help with yours make sure to share it over at Tangler.