Evernote's ambitious slogan is "Remember Everything." While it may be impossible to live up to that bold claim (at least until we get microchips implanted into our brains), Evernote does a terrific job at note-taking, for items big and small.
If you are not familiar with Evernote, you may have seen their logo before across the web, a gray elephant on a green background. In fact, there's even an Evernote button on every post on this site. That's one of the things that makes Evernote work; it allows you to not only remember everything, it allows you to remember everywhere. Evernote includes a vast library of desktop apps, mobile apps, and browser extensions, allowing you to take notes from virtually anywhere. Evernote also integrates with a number of third-party apps, allowing you to add even more content into your Evernote account. They have a repository of these apps in the Evernote Trunk (get it?).
Another major selling point of Evernote is the price: FREE. You're probably asking yourself, "What's the catch? They can't stay in business giving away a service for free." Well, it's a freemium service. The basic accounts are free, but you can pay for more features. However, the free version of Evernote is fully functional. The only features that you don't get in the free version are PDF search and offline notebooks on the mobile apps. The free version also includes less storage, but you still get plenty.
Speaking of storage, the way Evernote calculates space usage is unique; you get a set quota each month. So, your total storage is always growing. The free accounts get 60MB per month, while the premium accounts get 1GB of uploads per month. Note that these do not roll over, so if they aren't used that month, you don't get to keep them.
Evernote supports notes in the forms of textual notes created in the Evernote app, photos, audio recordings, pen notes (on Windows only), and files such as PDFs and Word documents. The note editor does not have every feature you could ask for, but it has enough features to be useful.
Evernote is available for Windows, Mac, iOS, Android, BlackBerry, Windows Phone 7, and WebOS. Evernote also offers browser extensions for Firefox, Chrome, Safari, and Internet Explorer, and they offer a bookmarklet for all other browsers. The apps and extensions are all free, and an Evernote Premium account costs $5 per month or $45 per year.