If you find yourself coming across a great article, blog post, etc., and you just don't have time to read it right now, you can save it for later with Read It Later, a Firefox extension that you can use to shelve content until you can get to it.
Once you click on the bookmark's Save button, the Web page will be scrubbed of any extraneous content (ads). You can then put it aside for offline reading or online reading, whatever you prefer, and no, you do NOT need an Internet connection, which makes it even more useful if you have a Web-enabled mobile device and have some time to kill. Read It Later is supported not only for Firefox, but also as an app for the iPhone, Twitter, Google Reader, Blackberry, your Desktop, and lots more.
More useful Firefox addons
The Top Ten Best Firefox Extensions: Firefox extensions "are small add-ons that add new functionality to Mozilla applications. They can add anything from a toolbar button to a completely new feature. They allow the application to be customized to fit the personal needs of each user if they need additional features, while minimizing the size of the application itself" (from the official Firefox Extensions site). Here are my picks for the Top Ten Best Firefox Extensions for searching the Web.