Where to start

I just finished a summer coursee in Web 2.0 technology and I have to say that I find it very exciting. There is so much information but I am trying to narrow down a couple of ideas to use in m math classes. Has anyone out there used blogging an a math class? Or any class for that maatter?I have found a couple of classes which use it and I'm intrigued. My students love to use messenger, facebook etc so it's not really a big step to move to blogging, it's just that they would have something concrete to talk about.