Opinion on this belly fat exercise?

[Davidnodavid]

http://www.youtube.com/watch?v=4uQtPyWkXcc&lc=1UqGnmWrBuKXrJuJp5AhpNVK18rZUFtikTv6tzzMOCg&feature=inbox

Do you guys think it is a very effective exercise? If so, how many a day should I do to maximize it?