Kinect only supports two players, Move supports two-ish

[Cross-X]

Here's an article from TheSixthAxis about this matter:

"Indeed, even the press release for dancing title Zumba appears to firm up the suspicions.

“Zumba instructor, the stage transforms into a high voltage party atmosphere with special effects and additional crowd dancers,” says the press release. “Players can also grow that party at home with up to four players on Wii  and PlayStation Move, and up to two players on Kinect for Xbox 360.”

http://www.thesixthaxis.com/2010/06/21/kinect-limited-to-two-players/

So there you have it. Wii is 1 up Kinect.