TopCoder - your opinion?

Hi,

What's your opinion on TopCoder.com and similar algorithm solving competitions like ACM? Anyone competing? I think it is a really good way to improve one's thinking skills -- granted, it does not measure your complete skill set(as programming isn't just algorithms), but algorithms are essential.

I think most people in the web 2.0 space are in it mainly for the money. The applications themselves are mostly pretty trivial from an algorithmic point of view, so I am really curious what's your opinion on this.

Or is everybody just on the road to change the world (with apps like twitter), and doesn't care about competitions like this(where hacking and bright solutions are still appreciated)?