Your Privacy, Meet Silver Platter
For the record, I don't like Beacon. There are just some things I don't want to share with my friends, and more things I don't want to share with the Facebook databases. However, I'm less surprised by these events than some of my friends seem to be. Yes, it should be possible opt-out totally, or better still, opt-in if you want to. Yes, you should be able to control what goes in your newsfeed.
If you think Facebook is invading your privacy, though, you haven't stopped to think about what Facebook is, and what it does. When you join Facebook, you more or less hand them your privacy on a silver platter, and you give a little more every time you add an app. What you're really asking for is Facebook to pretend they don't have your privacy by the wrist, like some heroine on the cover of a bodice-ripper, waiting to protest mildly when she is finally taken by the pirate king.
Fortunately, because many of the features of Facebook are neat, there are technical means of disrupting the beaconstream between third party sites and Facebook, at least until Facebook decides to change their beacon URLs. The safest thing to do, though, and the thing that would send the strongest message, would be to delete our Facebooks accounts en masse.
But none of the messages I've received from my friends suggest they're lining up to do that.