Honestly, we're a little surprised that it took this long for OneNote to land on OS X -- Microsoft's powerful tool for taking and organizing notes has been around for a decade now. Oddly it came to iOS and Android before finally finding a home in the Mac version of the Office suite of products. With its launch on Apple desktops, OneNote is also going completely gratis. The new Mac version is available for free in the App Store and the Windows edition is becoming a free download as well. The Metro-fied version designed for Windows 8 has been free for sometime now, but the full desktop version of OneNote 2013 was a paid part of the Office productivity suite. Premium features, like SharePoint support and Outlook integration still require you to cough up some cash, however.