I never found a good usecase for onenote's tags - yes, you can mark them as contacts or addresses, and there are handly shortcuts for that - but what is the use? How do you, for example, just view all elements tagged "contacts"? Or even just pages that have those tags? After all is said and done, it is probably easier to just type in the tag name as part of the data and let the search engine handle it.

(EDIT: cancel that, I'm an idiot. I just found a big honking "Find Tags" button right on the main ribbon that I'd completely overlooked before.)

I never understood the appeal of storing the entire freaking notebook in a single file either. When I started using onenote, I used the webcam recording feature as a sort of video diary, and this completely broke down my backup scripts (I put everything on amazon s3, which doesn't support diffs.)

/ end rant

Back to your comment, I don't quite understand what you mean by the online spreadsheet integration. Could you elaborate? I mean, the contacts integration with Outlook is pretty cool, but is virtually useless with anything else in the universe. What is the advantage here?