Dave Winer wrote a timely piece this morning about how Facebook is scaring him since the new API allows applications to post status items to your Facebook timeline without a users intervention. It is an extension of Facebook Instant and they call it frictionless sharing. The privacy concern here is that because you no longer have to explicitly opt-in to share an item, you may accidentally share a page or an event that you did not intend others to see.
The advice is to log out of Facebook. But logging out of Facebook only de-authorizes your browser from the web application, a number of cookies (including your account number) are still sent along to all requests to facebook.com. Even if you are logged out, Facebook still knows and can track every page you visit. The only solution is to delete every Facebook cookie in your browser, or to use a separate browser for Facebook interactions.
Personally, I like to log into facebook, go and read anarchist sites, watch some people vs animal pornography, and then visit catholic church sites and write about how much I admire the Pope. But, that's me.
On a more serious note, the war on privacy is one that has been going on for a long time, and Facebook is just another block in it. I suspect, no matter how terrible it is to say this, that one day we will have no real privacy--and that the mix of conservatism and capitalism that has led the push to this will, eventually, come under attack. Indeed, it may be that that day is already here, on both accounts. I don't really see how the continual financial issues throughout the world can sustain the way countries and economies are run and I think that what we are seeing, especially in Europe, is the start of a change, though what it will be, I don't know. The recent win of the French socialist party in upper house elections, the first time since the late fifties, supports this I think--unless, y'know, it turns out to be a blip in the system.