Digg is a social bookmarking site. Members of the Digg community send in links to content (articles, blog posts, etc.) that they find interesting. Other Digg members take a look at the submissions and see what they think. If enough members “Digg” the content then it will move to the front page of Digg. Many, many people go to the front page of Digg just to see what’s going on in the world. Having a link to your site there could bring in lots of new visitors.
Other social bookmarking sites are: