Another site you might want to try out is http://editthis.info/create_your_own...ture/Main_Page
, under Adult Stories. It's a wiki format, which I don't like as much as Chyoo's, although there are some upsides to it. I find it harder to navigate stories there, and to find new threads. The site can also be somewhat slow. I know that some Chyoo authors frequent it, just based on some stories being copied over to it, such as "In Space No One Can Hear You Breed". It also has a more "anything goes" approach to it's stories, meaning that the lack of limits there might not be for everyone, and indeed could be a liability to the site long term.