Re: Boo Hoo! @SVV
In any civilised society naive or uninformed people do indeed have to be protected so far as is reasonably possible (and from what I've read, I consider fb to be culpable in part here). But education is part of that protection; if your students only communicate via fb then perhaps they should be expected to learn to use email or whatever system your institution defines as a standard.
If you were aware of possible issues with fb, then due diligence would surely lead you to avoid it and to specify some other medium. Presumably you have a standard language that is mandatory for verbal and written communication with students, and I don't see why there's a problem in specifying other standards for communications, instead of pandering to the latest fad.