Wikipedia
Evernote is a cross-platform, freemium app designed for note taking, organizing, and archiving. It is developed by the Evernote Corporation, a private company headquartered in Redwood City, California. The app allows users to create a "note" which can be a piece of formatted text, a full webpage or webpage excerpt, a photograph, a voice memo, or a handwritten "ink" note. Notes can also have file attachments. Notebooks can be added to a stack while notes can be sorted into a notebook, tagged, annotated, edited, given comments, searched, and exported as part of a notebook.
Evernote supports a number of operating system platforms (including OS X, iOS, Chrome OS, Android, Microsoft Windows, Windows Phone, BlackBerry 10, and webOS) and also offers online synchronization and backup services.
Evernote is available in a paid version or a more restricted free version. Use of the online service is free up to a certain monthly usage limit, with additional monthly use reserved for Plus subscribers, and unlimited monthly use for Premium customers.