Then I still don't see how this is different from a wiki, or a pure collaborative document, or a federated wiki.

It's taking serious effort to try to work out what pain this solves that isn't catered for by the above options.

I don't see how this is different from a Google doc, where you have one doc owner and you can set permissions so that other people can view, edit, or only leave a comment?

Agree with you Matt. Check out the google docs promo vids they used during day 2 of Google IO.

(wow this was painful to find)

http://www.youtube.com/watch?v=tPtJd6AzU8c&feature=youtu...

That style of fun product demonstration would be perfect for this type of app.

Also google docs now work offline really well and across multiple devices, which is incredibly useful.

Who gets attribution for every thought embodied in that doc?

I believe Google Docs keeps all the revisions, so if anyone cares a lot, they could go back and check.

But what I've found with Google Docs is that if someone is making a trivial change (like correcting a typo), they'll just go ahead and make the edit in the doc. If they're suggesting a substantial change, they'll add the suggestion as a comment and let the author decide whether to incorporate it.