The number is certainly believable. Extrapolating from my own MySpace app, they would make $22.5M annually. Doesn't surprise me that they are able to monetize a lot better ($100M), considering how much more addictive their games are and their scale benefits.
I haven't downloaded this, because I've got an iPod touch and my college has no wireless. Is there anything that I could do WITHOUT wireless, or would I pretty much be screwed when I go back in a few days?