I would have to say that Stumbleupon brings me hundreds of visitors daily with Twitter coming in second and Kirtsy coming in third.
I've never experimented with Facebook, don't like Plurk, and don't even know what Mebo is:/
Facebook, hands-down. I think it's because the people I'm actually friends with in real life are easier to attract to new posts then cyber friends. I haven't really gotten a system down yet with Twitter and I only recently joined StumbleUpon.
Nacia (Moms in Boyland)
Will someone please explain (in depth) to Grandma here, what Twitter is and what to do with it? Do I put it on my blog? How do you Twitter?
Twitter seems like it's good for spreading the word about a blog. No followers yet though... :(