I think that postings on blogs can be informative, creative, or sometimes just boastful and self-serving. Since a weblog - i.e., a blog - is a sort of journal that people write for the world to see and comment on, it can take many forms depending on the author: some are interesting, some are a waste of time. Most teacher-made blogs seem to be serious in their purpose and utilitarian in nature. I like the idea of posting my ideas, comments, and insights so that others can give their input.
This is a blog for Paul Krugman, an economist and a writer for the NY Times who I follow and learn from all the time.