Chad Perin of Tech Republic has written a good overview of the privacy issues of Facebook including the general philosophy of the guy running it, Mark Zuckerberg.
http://blogs.techrepublic.com.com/security/?p=4708&tag=nl.e101
Basically do not put anything on Facebook that you don’t want either public or handed to some business. That includes the private ‘only me’ information.
Diaspora is mentioned in the article. This is an open source social networking platform, similar the Facebook but much more secure and privacy aware. It’s not quit ready yet but when it is we should all jump ship.