[John Gruber has a decent solution for blocking the DiggBar][link] on his site, Daring Fireball, if you’d like to completely block all Digg traffic.
I’m going to whip up a WordPress Plugin for this today.
[link]: http://daringfireball.net/2009/04/how_to_block_the_diggbar “Daring Fireball: How to Block the DiggBar”