Congrats to both sites, although I rarely visit Digg anymore and am addicted to Facebook. Honestly, I'd rather have the market that Facebook has, rather than the Digg market. I believe because of it's start, Facebook has a solid hold on the college age market, while digg has a nice footing in the geek area.
Thought this was quite interesting: "Average stay on MySpace is 2x more time than on Facebook." What you think? Comment 4 was also quite interesting!