Digg is one of the most popular social-bookmarking services. There you discover and share content by submitting links and stories from anyhwere on the Internet and vote up or down the stories. Voting up is called digging, and voting down is called burying. The most dugg and popular stories get to the front page.
Such sites are usually blocked at work places like schools, offices etc. Here are a few alternate URLs that could be used to access Digg where it is blocked.