Matthew Joughin (9/29/2011)
I would say the way pioneered by http://www.StackOverflow.com is the best way, where responses are voted for, but you can only vote for a response if you have "credibility".So then the person who finds the question later has a good indication of which the correct responses. I have found this works very well, and in fact have yet to find a question posted on Stackoverflow, which has voted answers, that didn't work as per the most voted answer!
They have a api called StackExchange which allows anyone to set up the same type of site, perhaps that should be looked into...
Gail and Gus have some good points. StackOverflow works great in some ways, not so great in others. The answers and suggestions are disjointed, and there is a lot of information in the comments because the format doesn't lend itself well to many questions. Works great for some, not for others.
It also doesn't necessarily help someone learn, or tease out why it's a good answer. The reordering of items also makes it hard to come into the thread later and figure out what happened, especially as items get edited and comments/answers no long apply.
We are considering implementing some ideas that are similar to SO, but not it exactly. The StackExchange API isn't open, nor could we use it here. Right now there are two large projects (blog changes, Simple Talk migration) that are holding up some work, but voting/rating/etc are probably next. Likely something we do and deploy in early 2012.