This is an interesting example of a community-built web service that's been around for a long time. Anyone can get a free account to ask questions. Question askers get points that can be assigned to the best answer. So the volunteer answering staff is highly motivated to give a good quality answer.

Premium account lets you read all the old questions and answers. A knowledge base of over 10 years that's not otherwise available on the open web. Premium account can be paid-for with points earned from answering questions, or by paying about $13 a month.

DanFr: I often get directed there by Google, but when I visit, it's covered in ads, and "I'll show you the answer if you'll make a login" and stuff, so I don't go in. (added at 07:07:39 PM on 03/02/08)