Jeff: I recently found stackoverflow.com and am addicted. What's funny is that I work as a Linux admin in support for a large hosting company and my day job revolves around answering customer's technical questions -- so why would I be addicted to a site where I can answer (or ask) technical questions without being paid? Yeah...it's because that's what I enjoy doing, for one, and that I enjoy the game of answering a question best.
Oh, and I hate Experts Exchange with a passion (even though the registration required answer is available without registration I just feel dirty visiting that site) and refuse to use it.
I'm actually thinking of ways to incorporate some of your ideas in my day job...some because as appealing voting down a customer's question might make a BOFH feel it's probably not the best way to treat customers .