Evernote is the ultimate productivity app for keeping your notes, reminders and to-do lists all in one place. It’s used extensively to save, edit and share notes among different devices and with multiple users. It works great for group collaborations and is great to jot down ideas on-the-go. Essentially a notebook stored in the cloud, the app helps you get (and stay) organized. Getting started can be tricky, so if you've never used Evernote before, make sure to check out Mashable beginner's guide.