From the comments regarding FB's IPO on HN in general, I am under the impression that the point of an IPO is to gain the company as much money as possible, and that in this regard, Facebook's IPO was a resounding success.
From the point of view of an investor, though, the IPO was a huge failure. Knowing, then, that any company approaching an IPO is trying to get as much money as possible from its initial investors, why would anyone want to be one? Is it solely because they are hoping that the company will be wrong about its own potential measure of success? Or was the Facebook IPO somehow different than an "average" one?