the process starts with reading what other people have written and editing that content for depth and relevance and accuracy. It's making connections about that content to other ideas to clarify what's important about it. It's adding personal reflection to give it context because only in knowing how the blogger experiences what she is writing about can I as a reader decide whether her ideas are worth my time. And, finally, it's linking back to that content so that the ideas can be traced to their genesis.
Blogs become tools of meta-thinking. Students are not just reading and responding, they are considering their own relationships to what they and other students think. In The Network is the Blog, Jon Udell says blogs are meaningful only when connected to the blog network. Much like a student paper often fails to consider an audience beyond the teacher, a blog that is not actively engaged in may as well be a piece of paper in a drawer.
This is part of the engagement answer, too. Writing with an audience in mind, an audience that exists within the classroom but also, potentially, beyond its walls, is a motivator to put time and consideration into what is said.
The pieces are all floating around for me right now, but there are threads developing between them, pulling them together.