Despite being a computer person, I have always had a strong preference for face to face discussions rather than email or blog posts. In general, people feel comfortable posting things that they would never say in person.
I do like to follow several blogs in my personal life: bleedcubbieblue (the official blog of the Chicago Cubs) and Illiniloyalty (the official sports blog of the University of Illinois). On both I have read thousands of posts, but never posted anything myself.
Calculus blogs that I visited are listed below. The best/most inspiring one is the first one by San Diego teacher Jonathan Winn.