Modern-day caveman Mark Zuckerberg revealed at last week’s F8 conference for Facebook’s developers that he’s recently added bison to the list of animals he’s shot, killed, and eaten. Zuckerberg also discussed a new advertising approach that’s already sparked the ire of privacy advocates who insist that the social network is not keeping users in the loop about how their personal information is being used. Advertisers and Facebook have teamed up to create personalized product endorsements based on users' activities not just on the site but elsewhere on the Internet. The plan is for advertisers to create “sponsored stories” about particular Facebook friends based on what songs they’ve been listening to, movies they’ve watched, or articles they’ve read. Some question the ethics of such advertising techniques, pointing out that just because someone has watched a movie on Netflix or listened to a song on Spotify doesn’t mean they liked it or would recommend it to their friends. “It’s turning your interaction with a Facebook business partner into a default endorsement. That can’t be right,” the director of an electronic-privacy lobbying group said.