I don't know if this has been brought up before or not, but here goes.
We all from time to time like joining doubles games. Frequently, players are picky about games they want to join, however. Lower ranked players (like myself) sometimes want to play doubles against higher ranked players, both for the challenge and the points oppurtunity. This is difficult however if your teammate isn't on at the same time you are. One way to get around this is to give your mate your password, so they can log in as you and join for you. But, here's my suggestion on it.
When joining a doubles game, have an option to reserve a slot. For example, click "join game". You are then given an option to reserve the next slot (next 2 in triples) for a teammate. If you click yes, you type in the name of the player you wish to reserve the slot for. This player is then notified. Could be done through PM, or perhaps, create a new tab on the My Games section, called Reserved, and you could put a 1 new flag on it, just like the Inbox tab, when you have a new one. The reserved player is then given the option of joining or passing on the game. Put a time limit on it, 24 hours would be fair. If the player passes, or misses the deadline, then the game returns to the main pool, and the player who offered the reservation doesn't get to reserve the spot again, it becomes random.
Anyway, that's my idea, any thoughts on this?