StumbleUpon helps you surf the web. It is a free tool which lets you browse, review and share great webpages while meeting new people. StumbleUpon is an intelligent browsing tool for sharing and discovering great websites.
As you click Stumble! , you'll get high-quality pages matched to your personal preferences. These pages have been explicitly recommended (rated I like it) by friends and other SU members with similar interests.
Rating these sites shares them with your friends and peers – you will automatically 'stumble upon' each others favorites sites.In effect, StumbleUpon's members collectively share the best sites on the web.
You can share any site by simply clicking I like it. This passes the page on to friends and like-minded people – letting them "stumble upon" all the great sites you discover.