Teachers will often start a blog for providing communication to students, parents, or other teachers. Sometimes this is just the posting of homework or other assignments in one easy-to-find location. Other times this can be a richer description of the things taking place in the classroom, specifically drawing the parents into what their children are working on, or for students who have been absent. Blogs can also take advantage of the comment feature for students and parents to ask questions or for clarification, where the answer would be of interest to all the readers.
Another benefit to educational blogging is the opportunity for the student to find a personal "voice" and to develop individual interests. Much like journal-writing, blogging gives wings to ideas that otherwise may can stay trapped in the mind. Many individuals find that blog-writing changes their lives in a significant way by allowing them to express their ideas in a medium that appears to have life and longevity--and that might find a kindred audience.
I think we can use some instructional methods in blogs such as demonstration because we can share a lot of presentations with nice slides to get a better idea of the topic we are learning. Discussion because we can share our ideas about whatever we are reading or watching. And tutorial because is an easy way to keep in communication with your classmates, students or teachers.
