We're experimenting with using Community Server for internal knowledge sharing at my current client (for IT folks only). We have a Sharepoint site setup that we use for posting tips/tricks and all that good stuff. But a lot of the knowledge sharing that goes on is via e-mail. And, e-mail gets purged periodically and requires that everyone keeps a copy of it if they think it is something worth keeping. We're playing around with using forums to toss ideas back and forth and provide solutions for each other. I'm optimistic that it will be a big success--just need to get enough people to buy in to it so it is a useful tool. We've always wanted to put out a newsletter periodically from the corporate IT staff to the remote folks. I think we can utilize a blog for that. I just wish I was the one who thought of using CS like this!
I've been at companies where we tried to use Exchange public folders for similar things but it never went over very well. CS seems like it could be an extremely useful tool for this type of thing. So easy to use...