Those old, slightly racist, pervy uncles you have friended on Facebook who either don't quite know how that page works, or just don't give a shit if you see that they like pages that only post pics of 20-something bikini babes, anti-Muslim pics and sexist shit. God I hope I'll live long enough to embarrass all my young politically correct nieces and nephews when holo-VR neural social networking takes off in 40 years time.
Oh, and while I haven't seen my aforementioned pervy uncle do this, I'm pretty sure those FB share buttons on porn vids are aimed at that demographic. Damn am I gonna share with the whole world every time my Viagra kicks in while I'm watching Ginger McTits and Sugar Pie Have Fun With The Pizza Guy in full holo-reality in the future.