In another subtle and seamless aspect of the OneNote 2010 user experience, OneNote's collaboration capabilities also support concurrent authoring, with near-same-time update synchronization. If I had been viewing the "Looks like a great resource" page shown in Figure 5 as Demo was adding the comment "Done - ordered 3 copies; they should be here next week," Demo's activity (content addition) would have appeared automatically in my page view. In my experience with the OneNote 2010 and OneNote Web App client (in Internet Explorer, Firefox, and Chrome), the synchronization of edits, when multiple people are viewing and/or editing the same page, takes around 30 seconds. The concurrent authoring feature can seem like a bit of a ghost-in-the-machine experience until you get used to the convention, but it can be a big help in facilitating timely collaboration.
OneNote's concurrent authoring capabilities are in many respects similar to what Google envisioned for Google Wave, an ambitious same-time collaboration service that was deemphasized (essentially terminated, although Google open-sourced the Wave code base) after it failed to attract a large user base. OneNote doesn't offer the same interaction granularity or immediacy (Google Wave displayed characters as they were typed, which always seemed like communication overkill to me), but it nonetheless facilitates a very compelling form of near-same-time collaboration.
Although these capabilities may appear to be seamless and intuitive from a user experience point of view, incidentally, they entail some elaborate database services, as described in my previous article "Microsoft OneNote as a Distributed Information Item Database System." OneNote 2010 represents a very significant investment on Microsoft's part over the last decade, especially when considered in conjunction with SkyDrive and SharePoint, and the overall solution will be very difficult for Microsoft's competitors to address effectively.