Ginny I do take your point when you say that blaming FB is like blaming a car for speeding, perhaps I hadn't worded my comment very well.
However, the things that people post on Facebook does seem to cause a lot of falling outs, IYKWIM
I remember a couple of years ago when the company I was working for were recruiting, one of the admin assistants was given the job of creating an initial shortlist of candidates.
And what was one of the "tools" she used? Yes, Facebook. She would look at their pages and if there were comments such as "got really drunk last night, so threw a sickie" you can guess the outcome.
I suppose the bottom line might be, don't put anything on Facebook that you wouldn't want to see splashed across a newspaper.