Why OneNote Isn't Yet Completely Mainstream
Considering OneNote's simplicity, scope, and utility, you may be wondering why the application isn't more widely known. Microsoft hasn't published the number of active OneNote users, but the OneNote user population likely is measured in single- or double-digit millions, while more mainstream Office applications such as Word and Outlook are used by hundreds of millions of people worldwide.
There are several reasons why OneNote isn't more widely used today, ranging from historical marketing and product licensing constraints to an argument that OneNote was initially a bit ahead of its time.
From a marketing point of view, OneNote's early and close association with Microsoft's Tablet PC platform made many people assume that OneNote was designed primarily for tablet devices and digital ink. In reality, OneNote has always been a powerful tool for traditional PCs, although it also fully leverages tablet-oriented capabilities. In any case, the lackluster sales of Tablet PC devices almost certainly limited OneNote's historical market penetration.
Microsoft also constrained OneNote sales, especially in Office 2007, by making OneNote relatively difficult and expensive to acquire. For example, OneNote was included in student-oriented versions of Office, but not in Office 2007 Standard or Professional Plus, the editions most commonly used by business organizations. OneNote 2010 is included in all Office 2010 editions, so this constraint is no longer an issue.
Earlier versions of OneNote also had some problems, including a peer-to-peer shared notebook model in OneNote 2007 that wasn't robust — it couldn't share information across corporate firewalls, for instance. In contrast, the shared notebook model in OneNote 2010 is completely revised; it's based on a cloud-oriented synchronization model (through SkyDrive and SharePoint) rather than a peer-to-peer model.