I'd second onenote for multiple user whiteboarding and brainstorming. It's a great program designed for this purpose, for quickly jotting down your thoughts. Al

I'd second onenote for multiple user whiteboarding and brainstorming. It's a great program designed for this purpose, for quickly jotting down your thoughts. Also it has handwriting recognition if you're a table user. Personally I use Google Sites' wiki for single-person brainstorming because I can access it anywhere. Also Google Sites supports secure https and true 'private' sites.