Teacher Blogs?

Interestingly enough, on Saturday I had to take a New York State exam and one of the questions on it was how as a teacher can I establish collaboration in my classroom.  One of my answers was by creating a blog and encourage students, parents, other teachers, and community members to reply or make postings!  I think it would be another great way of increasing communication between teachers and students as well as a lot more.  What do you think of this?  Can a blog really help increase communication between teachers, students, and everyone else?  Do you like the idea?