I have no idea if this link is persistant or not; but, at the moment it shows that Digg has surpassed Slashdot in the Netcraft toolbar ratings. Slashdot is the #513 most visited web site on the planet, and Digg is #512. Google is still #1.
At one time, Slashdot was ranked #25 world-wide by Netcraft.
It will have fallen to The Onion less than 30 ticks from now.
Of course, sites like Facebook, MySpace, Bebo, Friendster, YouTube, Engadget and Blogger bumped the 'dot out of the rankings by going after larger audiences. Although I don't know of anything that made it impossible for Taco and friends to cater to those people.
Other sites, like Weather.com, Foxsports, Wikipedia, Drudge Report, Woot, - they all blew past Slashdot - but they aren't really interactive content sites. They publish, you read. It's a different paradigm. The 'dot is all about community.
The fundamental question that is left: how long before Slashdot is less popular than I Can Has Cheezburger?
100 ticks and counting....
You Digg it?