The Journal's report jumps off a 2009 study that suggested just this kind of personal data "leaking" might be occurring. But this is the first time Facebook actually acknowledged that they shared personally identifiable data with advertisers. Shortly after being contacted by the WSJ, Facebook revamped their code to hide the usernames in URLs.
We already knew that Mark Zuckerberg knows when you're going to break up with your girlfriend. Now imagine that the last time you clicked on that Papa John's Pizza ad, some bored Papa John's advertising exec was looking at a picture of you all flabby on the beach and laughing his ass off. (via Ars Technica)