21Classes: http://www.21classes.com/
Before this web site, teachers who wanted to use blogs in their classrooms often had to use sites that contained ads, linked students' blogs to other blogs all over the internet (many of which were not at all suitable for children) and that left student blogs open for the general public. 21 Classes provides a classroom homepage where a teacher can post assignments and other information. This is also the place where students can access the class blogs--each student has their own blog. Teachers and schools can purchase additional features very (including their own domain) inexpensively.