Heard about the news that Facebook is going to launch a new advertising model where they target ads based on user's browsing history. [1,2,3] From what I understood, FB is not going to (and unable to track) your complete browsing history; rather, FB is going to build a browsing profile for you based on what you explicitly want to "like" by clicking a button placed on a web page you browse. I think they already get some amount of browsing history information whenever you click "f-share" button on a web page which sends the request to http://facebook.com/.
The question is whether this behavioral targeting is an invation/violation of privacy? IMO, it's NOT a violation of privacy as opposed to what the links above try to indicate. Privacy is more about the control YOU have and less about secrecy. Unless YOU explicitly decide to like or share (by clicking), FB will not be able to do any meaningful behavioral targeting. It's still under YOUR control.
Of course, it is a violation of privacy, if FB tries to show ads to someone based on YOUR browsing history which they tried to do with beacon system and failed miserably; YOU loose control over YOUR data in this case. I think FB is not going do something similar to that with the new behavioral targeting.
Waiting to see how their system actually works!