So basically a forum? Knowledge Management is a broad topic and it's hilarious seeing the same solutions brought up again and again.
I have all this persistent information! New people need to get up to speed fast - where do I put it? Cue the Wiki fad.
I have to get things done and elicit quick feedback ASAP! Cue the Chat fad.
I want async communication so I'm not bogged down all the time! Email and Forums.
There's a time and place for all of these.