Something about the casual nature of blogging allows me to just write, less concerned about what people are thinking. Blogging can be almost like a stream of consciousness, perhaps on one specific field (like educational technology) or on your whole life. It gives us a sort of freedom that is lost in an endless stream of assigned topics and required papers. And maybe too, something about the anonymity of the Internet, even when people I know are reading it as well, is freeing.
But the best thing about blogging, I think, is that it is not just a platform for writing, but one for discussion, with the comment sections often becoming the most interesting aspect of the entire thread. Personally, I put more thought into written word than in conversation, the slower pace allowing me to check a citation or fact, or even at times going into several layers of research before composing an answer. Never before in our history has there been a platform for discussion like that (pre-Internet) - handwritten letters are slow, in-person and telephone conversations are quick, leaving less time for reflection and thought. Even emails are generally between two or a small group of people and generally have a different purpose.
It's nice to write again. Maybe I'll get to that book someday. ;)