Nintendo is still keeping their online play service a secret from developers. Which is troublesome for the system.
Nintendo still haven;t given the details of the Wii online service to developers yet. It quite a shame because some of Wii's steller titles would have just be ave been incredible to play online such as Super Smash Bros. Brawl. So here we despiratly have to wait for Nintendo to provide us with some more infomation.
Nintendo did the exact same thing with the GameCube, they announced online near the beginning and then later on went to release it. It was poor and was basically a failure with only 2 games truly utilizing it and a modem cost of 34.95USD