I don't think that many content owners do, and those that do are deluding themselves into thinking that the amount of dilution of their product is worth the sales they are getting.
Some companies are also burning all their old content this way, as we move to HD.
Some people spent a ton of money on content, made thier money back in the good times, and are now looking for the gravy sales.
In all cases, I don't think they are really paying attention to just how much money they are making for the xtube guys, who run huge numbers of unrelated ads on the pages, profitting from the content without giving back anywhere near a reasonable amount of traffic.
I have a feeling it may be a "bro" thing.
