BoingBoing links to a new chrome plugin that encrypts Facebook content so that not even Facebook can read it. I love this idea in general. Browser side encryption of content as it is posted and read from a webservice. This would obviously break a lot of bonuses that come with server-side processing, like search and suggestions but it sounds like a great option for sensitive data.
I don't use Facebook so I have no idea how well this works. I just like the concept and hope this becomes a more general solution for working on the web.