How can Blogs be used in the AP classroom?

There are millions of blogs on the Internet that range in topics from math to rock collecting. Blogs can be used as personal journals, as a communication tool between a principle and a school's parent community, or as practice for the AP exam. I currently run a blog for AP Environmental Science teachers around the world (http://goapes.blogspot.com). About every 7-10 days, I create a short post about an environmental topic, included some online resources and some AP-like exam questions about the issue, and have students post their response. It's also fun to include a Cluster Map (http://www.clustermaps.com), so you can see how many visitors you have and where they are in the world. With a blog you can encourage other AP classes to join and post their comments. Last year we had a group in Japan add their comments to a post we did on whaling. It was fun to have our students blog with them about an important issue and see the issue from a different perspective. Every once in a while, I have my students look at the blog of an environmental organization or a company and have them post a cogent response to an issue being discussed (http://goapes.wikispaces.com/Blogs%2C+Podcasts+and+Feeds). If you are interested in finding out whether there is a blog deals with topics in your AP topic, you can use Google Blog search (http://blogsearch.google.com). What is one blog site that would be appropriate for your AP students to use? And what issue did you find the most interesting?