I just noticed one site that does this well - it's not really a forum, but a q & a site:
http://fixya.com It's simple, and straight forward - you type an answer or 'I have the same problem' before you give them info. They reeled me in!
As a side note it looks like new forum platforms are starting to include better q & a support, like community server, and even
answer forums for vB. Something like this would work even better with a proper q & a setup.