You and Jeff are confused about what makes stackoverflow.com successful.

The reason stackoverflow is successful is because it's a clone of another successful tech Q&A site (experts-exchange.com) minus the scummy answer cloaking plus some social voting.

That's it.

All this stuff about the "right kinds" of questions being "key to its success" is based on absolutely nothing. There is nothing to support that. The one thing we do know is that deleting high quality user-generated content pisses people off.