Chris Pratley's OneNote Blog : OneNote 12 is now OneNote 2007, and it's in the box! "OneNote makes sense here of course not just because it is great for note taking and capturing information in a mobile environment but also because of the Shared Notebooks feature. If you are out of the office a lot, you need a collaboration system that doesn’t require you to have internet access in order to work. OneNote provides that via shared notebooks which are like super-rich wikis that you can use offline and then have changes you and others made sync up when you later get a net connection. Groove of course is a nice complement as it provides a workspace for shared documents, forms, etc that can also be used offline. You can read more about Groove at Marc Olson's blog."
Major progress in shared notebooks for OneNote 2007.