Lib Guides has been around for a while and I have written a few different posts on it but have you heard about Lib Answers yet?

Lib Answers aims to provide libraries with a public forum from which their patrons can ask questions. It is also customizable and can be used in combination with Twitter and Lib Guides.

Its built in community and database of answers which allows you and your patrons to search for previously answered questions is also a nice feature. Although I have not yet tried it, it sure does look promising.