Influencing friends in facebookJust finished submitting Feed Me: Motivating Newcomer Contribution in Social Network Sites ( PDF). The gist is that we analyzed a large group of newly registered FB users and counted all the things they did (or their friends did) in their first two weeks, and predicted how the newbies would behave three months later (how many photos they'd upload). We found that if their friends are uploading photos, they're more likely to, as well (no surprise). And early photo comments are good. But there are some surprises about tagging in there.
What makes this especially cool is that it's the first peer-reviewed publication to come from Facebook's own server data. We were somewhat skeptical about the company letting us publish at first, but the legal team was totally supportive about sharing knowledge with the world, and we were careful to use aggregate data so as to protect users' privacy. The awesome Facebook Data Team does all kinds of brilliant work, so hopefully this is the first of many papers to come from FB. Yay for science!