My Educational Technology 220 class has started a unit on blogging- students are required to set up their own blogs, and explore other blogs that may reflect what they'd like theirs to become. Teacher blogs are a fascinating thing- it's a way for students to connect with teachers outside the classroom, and it's a great way for teachers to post information that their students can then access easily.
Teacher blogs can take many forms. They can provide teachers with the opportunity to show off student work and classroom achievements, or they can be a useful, practical reference for students catching up on homework. An impressive example of the latter is Mr. Sondergroth's Homework Blog. It's not frilly, but it's a solid, frequently-updated resource for students and their parents. Take a look:
http://sgrothfam-hw.blogspot.com/2012/01/wednesday-january-18.html
On the other hand, some teacher find blogging a useful way of sharing everything their class is doing with parents, community members, and other teachers. One of my favorite examples of a "fully-loaded" blog is Mrs. Cassidy's Classroom blog:
http://classblogmeister.com/blog.php?blogger_id=1337
It's great that teachers have the freedom to share whatever information they find relevant and would like to share with their audience. Some schools require teachers to house their blogs (if they choose to have one) in a school- or district- sponsored network. However, most Teacher Bloggers use whatever blogging application they find the most useful to them. As my blog grows, I'll continually share the Teacher Blogs I find interesting.