Support forums are now a requirement for almost any business that has customers. Most support forums are hard to use, unorganized and look terrible. To illustrate some of these issues, I'm going to pick on the Logitech forums, which are powered by Lithium (http://forums.logitech.com).
One of the first things customers do when looking for support in your forums is to search. If your search isn't awesome or has any odd bugs, it will probably drive your customers crazy and they might give up and return the product instead of trying to fix it.
Here's the Logitech search bar: