Social bookmarking site Digg is incorporating the Nofollow tag to a bunch of links in order to reduce spam. Links on user profiles, comments and not-so-popular posts will get the nofollow tag, meaning it won't pass along link juice.
Many have submitted content to Digg just for the links. Of course, the more popular a link is, then there's the added value of a traffic bump.
In their blog post announcing the change, Digg was not specific on how popular a link would have to be in order to get the Nofollow tag removed.
Digg said it worked with leading experts in SEO to come up with the rule. But since Google bullied Twitter into integrating Nofollow, you have to wonder how much of a collaboration this was and who the experts were.