The most involved owner that I've seen on any of the sites would have to be 'Badger' on GT. It's not just a business venture for her, but more of a labor of love. Very active on the discussion boards and always working with the main programmer to develop new games. She's on a personal basis with many of the members. After her, I would say that Fencer is the second most involved owner. The rest of the sites (including IYT) seem to have no input or presence whatsoever from their owners.

I will say this of Fencer, though, he does seem to be very tolerant of criticism. There are very public complaints on here that would be moderated elsewhere.