StumbleUpon

From the StumbleUpon web site:

//StumbleUpon helps you discover and share great websites. As you click// **//Stumble!//** //, we deliver high-quality pages matched to your personal preferences. These pages have been explicitly recommended by your friends or one of// //6 million+// //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.//

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