Is Facebook trying to kill you?

From Blade Runner to the Matrix, from Star Trek’s Borg to Battlestar Galactica’s Cylons, we’ve spent a lot of time imagining the day when our super-strong, super-smart robots get tired of vacuuming and decide they want to rule the world. That’s given me an opportunity to consider a more immediate threat: Facebook. Not just Facebook, actually, but all the social networks and online communities to which we give our eyeballs, braincells, hearts and dollars. Could these online communities constitute the machine threat that sci-fi has taught us to anticipate?