I'm a soon to be webmaster but currntly just a porn consumer and I can tell you that the sites that are shooting in widescreen 16:9 HD (like Sean Cody) look amazing on my 42" flat screen TV, which I also use as my computer monitor through an HDMI hook up. I also have video productin experience and would recommend that if any would-be porn producer was starting out they should buy HD camcorders since the prices have come way down.

The thing with HD is once you see it you get spolied and don't want to watch anything else. I'm not a sports fan but I find myself stopping on football games and other sports shown in HD because the picture is so breathtaking.

So to answer your question, if I was tring to decide between two porn sites to join and everything was equal except that one was in HD, I would probably go with that one. In a competitive business like this it might be good to offer that extra icing on the cake.