StumbleUpon Firefox Add-on
StumbleUpon is both a social network and an excellent way to find fodder to share with your other social networks. It takes you to a "random" Web page (though "random" actually means customized according to your preferred categories) when you click a button. You can then tell StumbleUpon whether you "like" or "dislike" the page, and StumbleUpon's algorithm learns what types of "random" pages to show you, based on those preferences.
The StumbleUpon Firefox add-on not only lets you "stumble" and rate pages, but also gives you buttons for sharing pages with social networks (Facebook, Twitter) and by email, as well as buttons for interacting with the StumbleUpon community. In other words, this toolbar is perfect for content junkies who need fresh material.
Note: This link takes you to the vendor's site, where you can download the latest version of the software. You will need to sign up to use the StumbleUpon service.--Sarah Jacobsson Purewal