I also notice that most of my blogger friends who have Facebook accounts are also slowing down on blogging. (I am guilty for introducing Facebook to many of my blogger friends). Only those who are still "uninfected" by Facebook seem to still be actively blogging. I wrote on this in September last year, that Facebook is actually "killing" some of the activities that we do in the past.
I won't stop blogging though. But I won't be blogging as often as I used to.