In my little world, some kind of Facebook social network boundary seems to have been recently crossed.  People who have better things to do with their lives than tweet now have Facebook accounts.  I don’t know why that is, but Facebook, especially, seems to have become de rigueur all of a sudden amongst a much broader audience.  Honestly, I still don’t know what to do with Facebook and I do my best to do as little as possible with it in the hopes that it will go away and stop bothering me, like MySpace, but it has definitely moved from early adopter to broad adoption in my circles.