Evernote is a free note-taking application that can be used via the Web or using a client 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.
Evernote offers premium and business accounts which offer additional features, including the ability to save larger files and create presentations within Evernote.
Need some suggestions on how to organize your Evernote to improve your productivity? This article by Michael Hyatt shows you how to tag things more efficiently.
As part of the Office suite of tools, OneNote has a native Windows client, but also allows you to work online via a Live.com/Outlook.com account. If you have an iPad, iPhone, iPod touch, or Android device, there's also a free app that syncs with Microsoft's servers, allowing you access to your OneNote notebooks.
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 bookmarklet 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.