Circling back again, the more likely warpath FB would pursue is making FB work very poorly on non-cooperative browsers and excellently on cooperative ones.

Then users will blame the browser for being trash rather than FB.

Yes, that is one potential countermeasure. I wonder if it would be effective or if it would be the beginning of the end for fb.

>In 2015, it is expected that 70.1 percent of Facebook users worldwide will access the social network through their mobile phone.

What I don't know if that means browser or App. Not effective at all if most people use the app.