Looking to connect your students with other students through blogging. If you teach grades 1 and higher, you should check this blog to make connections: The Comments4Kids.
Even if your students are not blogging, they can still comment on other students' blogs. The Comments4Kids blog posts information about classes who are looking for others to write replies to blog posts.
The Comments4Kids would also be a good blog to follow in your Google Reader. William Chamberlain, a middle school teacher, maintains the blog and updates it often.