Found another way people are collaborating and sharing new cyoa's. iStory uses Google App ability to share a doc, but also has elements of popularity and quality control. From ridiculous to mundane there's all different kinds of stories here. It's not a very active site in terms of new content, but the coolest feature is that their software, Story Forge, creates an iphone version. It's also graphically friendly.
Here's another downloadable cyoa game back from the day: Romance in the Caribbean!
See also January's Infinite Story and March's cyoa Wiki.