I've started using this and it's proven to be super useful. I've really been enjoying the functionality here. Highly recommend if you need something to help you organize your campaigns.
For the uninformed: this site is mostly for GMs/STs/etc -- people who run roleplaying games of various sorts. D&D, WoD, CoC, etc. It helps you organize things by giving you access to a blog, wiki, forums, maps, character sheets, etc.