http://alexkrupp.typepad.com/sensemaking/2009/02/68-free-bus...

The point of the exercise is that most people think of five or ten ideas, and then go with the first decent idea they come up with. But if you actually force yourself to come up with 100+ ideas then it's more likely that your idea will legitimately be a good idea. Which is important since the first .1% of the work you do on the project has a large influence on whether the next 99.9% will make you either millions or zero.

Fred Wilson also recently said that he would use one of the 999 if someone made it, in case that means anything to those perusing the list.