Evernote is a free* note-taking application that can be used via the Web or for computer or mobile devices. You can use it to type notes, capture audio notes, and upload documents to your account; the company allows other software developers to work with it and as a result has many other software packages that will sync notes and documents with Evernote.
* the basic account is free, but there's a traffic limit. If you do a lot of syncing of large audio and video files to your Evernote account, you may be encouraged to upgrade to a paid plan. See this page for more info about Evernote.
Take notes the easy way. Download OneNote for free on your PC, Mac, phone, and tablet. Then gather all your ideas in your notebooks stored online with OneDrive, so they’re always with you.
Handwriting apps can be a fast way to take notes, especially if you find typing on a tablet keyboard difficult. You may, however, find it's easier writing with a touch-sensitive stylus, which adds another cost to the price of the tablet and app.
A handwriting app for the iPad, Noteshelf allows you to choose virtual paper designs appropriate to the kind of notes you'll be taking. You can also customize the covers of the books and save pages to your Evernote account.
Penultimate is developed by Evernote, and is a perennial favorite handwriting app for the iPad due to its functionality and low cost.
The Cornell note-taking method has been around for quite some time, first published in Walter Pauk's book How to Study in College, yet many people still swear by it. Gina Trapani wrote a nice introduction to it on Lifehacker.com. You can design and print your own custom note-taking paper if you want, or go with the original version.
One of the first bookmarking services to allow people to share links with one another, Delicious lets you save your bookmarks and subscribe to other users' streams when you find people with similar interests.
Save links for later reading with Instapaper, one of the most popular and well-known link-saver apps. Add the bookmark to your browser for quick storage, and access your articles while you're on the go.
Formerly Read It Later, Pocket is an app for iOS (Apple devices) or Android that lets you save articles to be read later. You can save material directly from your computer's Web browser, by e-mail, or via one of many mobile applications. The service and app are free.