StumbleUpon.com

Stumble!

I actually stumbled upon http://www.stumbleupon.com/ It took me a few minutes to figure this out but this is very cool. Here the definition of what it is:

StumbleUpon lets you discover and share great websites. As you click Stumble!, they deliver high-quality pages matched to your personal preferences. These pages have been explicitly recommended by your friends or one of 6,499,238 other websurfers with interests similar to you. Rating these sites you like () automatically shares them with like-minded people – and helps you discover great sites your friends recommend.
How Does it Work?
StumbleUpon uses / ratings to form collaborative opinions on website quality. When you stumble, you will only see pages which friends and like-minded stumblers () have recommended. This helps you discover great content you probably wouldn't find using a search engine.