Mac: Popular archiving tool Evernote today released a new beta version for OS X users, adding the ability to share notebooks with other Evernote users and an option to sort notebooks by stacks. While some of these features have been present on Evernote's web version, it's new to their desktop application. Not to worry if you're a Windows user, the Evernote team is hard at work on updating their Windows client as well.
To upgrade to Evernote's beta, open the application on your machine, navigate to Preferences > Software Update and be sure the "Update to beta versions when available" box is checked.
Evernote Beta for Mac gets sharing and Notebook Stacks [Evernote]