Years ago software freedom fighters understood the harm Facebook poses and threatens. And they warned us all to avoid Facebook.
The Free Software Foundation got there earlier: the FSF published a warning on on Dec 20, 2010. FSF & GNU Project founder Richard Stallman has been rightly objecting to Facebook for years in his talks and on his personal website.
In his talks, long-time former FSF lawyer Eben Moglen rightly called Facebook a monstrous surveillance engine. He pointed out the ugliness of Facebook’s endless surveillance (at length in part 3 but in other places in the same lecture series as well). See http://snowdenandthefuture.info/ for the entire series of talks. Moglen routinely points out that ‘Stallman was right’ in his talks and for good reason.