The idea of micropayments comes to mind. I use an Online service (
www.istockphoto.com) to get free-use images for my marketing/graphic projects. I basically pay them an upfront amount (say $10 U.S.) which is then applied to my account. Whenever I download a picture, $.25 U.S. is deducted from my account.
This works nicely, it is not painful, and I believe that the money is put to good use in supporting the service and creators of the images.
To brainstorm for just a moment before I go back to working --
If Joe Gameplayer establishes an account at PBW, and knows that to play one game will cost him say ten cents per turn for his first game and say 2.5 cents per turn for every game after the first, it would be a low-pain way to bring in a revenue stream. Now...would that stream be enough? I do not know. But it may help.
This model is based not on the number of players, but on the number of turns played. If the cost structure where a graduated system where the more you play the less it costs per turn, then there is an incentive to play more.
I am just thinking out loud, while I add some cash to my paypal account and see about getting it over to PBW.
Just a thought.
Cheers!
Trajan