Digg is a community-based news article popularity website. Or social bookmarking site.News stories and websites are submitted by users, and then promoted to the front page through a user-based ranking system. Digg or other social bookmarketing sites often play a pivotal role in marketing a website online these days. However, unless you plan on writting unique articles or blog entery, digg or other social bookmarking submission buttons may be unnecessary.
Digg submission buttons allows an easy way for users to quickly submit your article or page to the digg website. The same holds true for other social bookmarking websites.