If your whiteboard has permanent maker on it, trace every permanent mark with an Expo, and let dry. Then erase everything, and it should come off.

Maybe under "search knowidea" you could somehow search people’s names (usernames or real names) to see what any given user has posted?

You should have a Halloween costumes section other than the "costumes" subsection under parties! And maybe one of the main categories should be holidays, since people like posting holiday id...