There's another question here which is what do you use FB for. I don't trust FB with my personal data so they have very very little of it and my involvement wi

There's another question here which is what do you use FB for. I don't trust FB with my personal data so they have very very little of it and my involvement with the site is largely passive consumption. This might add up by the time I've looked at pictures and read a bunch of stuff, but it's a very different level of engagement to those who post more - I could check it every day but it's far from an essential part of my life. (BTW - your selection bias issue hasn't gone away, it's still a self selecting poll, time is just one tiny factor).