James Farmer does some reflecting on what's working with blogs in education, pulling together some interesting links and references. The sub-sub title could have been "...and what's not working", because many of the cases he points to have had uneven success. It's certainly true that people are finally starting to understand that "if you build it, they will come" just doesn't work, particularly in mainstream education, which tends to take a conservative view of new technology.
We've been discussing this issue at work in the context of using blogs as part of a web-based portfolio to help students record and reflect on their future possibilities. We know that just providing the tool won't ensure that it gets used. My current angle is that students would only voluntarily use a tool like that if they had something they really cared about to reflect on, but most of what they're doing in school doesn't fall into that category. Teachers may assign projects using the tool if it's safe and simple, but the likelihood of students engaging in the process is certainly lessened by it being obligatory to begin with. As an aside, the xplana site is beautiful -- most blogs and sites in this field are functional and clean, but very few are so pleasing to the eye.