One of my friend's wives is chief of computer security for a big corporation. So she monitors how much time is wasted at various websites then applies filters depending on how many people spend too much time where.
The first sites she had to close down were surprisingly ...car parts catalogs, racing and football sites, then the matchmaker sites, then around a month before hunting season started last year she had to start filtering anything related to guns, outdoors and hunting.
Her decision wasn't political, just to save the company network costs related to hobbies.