Tens of millions of people provided personal information to Facebook with the understanding that this information was being shared only within their social network. Then Facebook changed the rules and this information was unexpectedly shared with perfect strangers. That is, simply stated, a profound invasion of privacy. In the United States, the Fourth and Ninth Amendments to the Constitution, along with numerous landmark Supreme Court cases, have established privacy as a fundamental right.
I am getting closer and closer to leaving Facebook. We will see, if all my friends used Flickr and Twitter it would be a no brainer. I only have one friend that does though (our of a possible 3 friends that I have).