I get the appeal of that. I wonder though if it make sense for a website built on collaboration to be exclusive? Not that those things are mutually exclusive, but it's similar to the right click to steal issue. If people want to steal something they will, so it's not worth sacrificing the user experience here (probably); similarly, if the exclusive feel prevents people from signing up there will be less collaboration.

I guess it partly comes down to what is meant by collaboration. Is it writing together? Is it just feedback like comments or Genius style annotations? I really like the idea of either. These questions and others the users had here could be answered on the landing page. If you guys are interested in more feedback as you progress feel free to hit me up!