In September 2012, Facebook posted that it had reached the one billion user mark. One in every seven people on the planet, Facebook beamed, has a Facebook account. Well, actually, Facebook only knows how many accounts it has, not how many people use it. Anthony Weiner, for example, probably had two accounts, one in his own name and one in the name of Carlos Danger.

A billion, a schmillion, whatever. Face­book has a lot of users — every one of them a potential gunshot to their own foot.