OneNote is a free form notepad that enables a user to copy and paste text, images, videos, and emails onto a page and save the page in a notebook within a folder.
Here is a screenshot of one page of information in my filing cabinet. At the top of the application window you see a ribbon toolbar, currently the HOME tab of the toolbar is selected. Each tab provides a toolbar with specific features that are quick to find and intuitive for new users. Just below the ribbon toolbar, the window is divided into 3 sections which are (from left to right) Notebooks, Folders, and Pages. The Notebooks section will list all of your notebooks. Currently we are viewing the BTG SOLUTIONS folder. In the first section you can see that this notebook is selected and you can see the folders that are defined within this notebook. In the middle section you are able to see a page found in the BTG DOMAIN folder entitled "Twitter Design - to follow colors on website". You can see the day, date and time this page was created. OneNote automatically adds the date and time stamp to your entries. The contents of this page is an image of a screen related to my Twitter account setup. In the third section on the right you can see each page within the BTG DOMAIN folder.
Here is a 30 second video prepared by Microsoft that demonstrates the power of OneNote.