On uncensored forums, people love to rage about FB, but it's just grandstanding (or is it showboating?). FB is what you use it for - I use it to keep in touch with the people I used to enjoy working with, and there are subgroups, such as the Open University or, more specifically, OU Classics. I have had two twitter accounts in the past and closed both without tweeting. The 140-character rule seems designed to prevent anyone from using a logical argument there. But I've noticed on FB that not even people I know with multiple university degrees regard logic as anything more than pedantry.
Glassy is a bit like a FB friend (ex work) I have who initiates provocative threads (e.g. "renting property is more ecologically sound than owning it") and never contributes to them after initiating them and never acknowledges having read any responses, so I think thread-drift is fair game.
1975 Calatayud y Gisbert, Yamaha CG131S.