Wikinomics is a very interesting book about mass collaboration. Oddly enough, it does not actually talk about wikis a lot, more about business collaboration and emergent behaviour, but it is a good read and I certainly recommended it.

As you would expect from a book with such a name, it does have an associated wiki and you could probably say that this is a 'web site with a book' rather than a 'book with a website'.

The best take away that I got from the web site was this diagram:

A picture tells a thousand words. You can see the original post about it here