Lurking -
I have a personal one - but would never have a "school only" one. Apparently there have been issues with teachers having one and then a link pops up, kids click it and it leads them somewhere, then somewhere else etc. and parents get upset, lawsuits etc. Too much liability for me. Also kids clicking on other kids FB pages that may be inappropiate or kids thinking that I'm looking at their inappropriate pages...you see where I'm going.
I'm not about to loose my job or credential over something stupid.