I probably should have chosen a different title when I first wrote about Yahoo Buzz. According to comScore, Yahoo Buzz has actually overtaken Digg with nearly 7 million monthly unique visitors in the U.S.
As always, these metrics must be taken with a grain of salt; also, one must take into account is that Yahoo is one of the top 5 sites overall according to most metrics, and that all their projects get a really nice kickstart from all that traffic. But still, I didn't expect such stellar growth for Yahoo Buzz, which seemed - it still does, in fact - like a lightweight version of Digg for less tech-savvy users.
My smart friend Muhammad Saleem seems to have been right when he predicted that Yahoo Buzz is actually a big draw for publishers who will swarm at the prospect of being featured on Yahoo's front page, while at the same time being a nice option for less-than-hardcore social media users, which is most of the world's population.
Furthermore, Yahoo Buzz has a more diverse audience than Digg. While Digg's young, male, techy audience has been the stuff of legend since the site's beginnings, 51% of Yahoo Buzz's visitors are women. This doesn't matter much to the users but it does matter a great deal to the advertisers; another legend has it that diggers never click on ads, and this might not hold true for Yahoo Buzz.