I can't remember which chess site has this (either redhotpawn.com or gameknot.com) but you can specify in your user profile how many moves per day you will make (either 1 move per day, a few moves per day, or many moves per day.) If we had this information on this site, then you could specify the minimum amount of moves per day required to join the game, or allow each player the option to abandon the game before making their first move if there were unsatisfactory players who joined the game.
(Not trying to threadjack here) Another idea is to incorporate a user-feedback system, like eBay. Only people who play a game through to completion (i.e. no deadbeats) can rate others in the game, and they can rate on 1 or more categories such as: (1) turn responsiveness, (2) sociability/cooperation, (3) anything else you could think of.. This might bloat your bandwidth and/or space limits lack so probably won't happen, just a thought.