Microsoft has just plumped up OneNote Online, and while it's not exactly a complete overhaul, the refresh adds features critical for cloud collaboration services. For instance, the update introduces a feature called People Presence, which shows all active users working on the same page as you are, so you can ping people if you need a brainstorming session. To prevent collaborators from overwriting each others' edits, Microsoft has also improved the service's syncing capabilities to reflect changes nearly in real time. These updates are already live on Office Online, where you can edit any OneNote notebook you or your friends share on OneDrive or Office 365. And, yes, you can enjoy the features no matter what OS (the software's available on several platforms) your friends used to upload.