Ok, one thing I've noticed on the PBW open games forum is the large ratio of Replacement Player Needed games to New Games.
Clearly people abandon games a lot.
I used to play Diplomacy (an excellent, excellent Avalon Hill board game, now published by Hasbro, I think) Online, and the mailing list that organized the games had an interesting system of ranking its members. I think something similar could be adopted for PBW.
Whenever a player saw a game through to completion (either by winning or participating in a draw) they were promoted to "Dip Knight". Players knew that a Dip Knight had proven themselves to be reliable (often by playing on for many many turns as a minor player, hovering on the edge of extinction) and usually pretty talented players. I gather that they were promoted as they completed more and more games and (although it didn't happen too often) that they could lose their status if they became unreliable.
Imagine, if you will, the creation of an order of PBW players of undisputed reliability and skill (like Jedi but without fancy swords). Hopefully an elite, but not elitist (hard to do).
You could apply for the first rank after surviving or winning a game of longer than, say, 100 turns?
Then, if a member of the "Order of Malfador"

joined your game, you'd have an idea of his/her calibre. Debate over the name (and indeed over the usefulness/appropriateness of the whole idea) is encouraged.