Digg is a site that posts popular news articles, pictures, games, videos, etc. The more people that 'digg' an item, the more likely it is to get on the front page and shared with others.
Yea, if you go to www.digg.com, it will take you to the website. They have a lot of cool things there. Plus, then you can Digg the games on this site. For example, I just Dugg Elements, because it is so awesome!