I've been using 21publish as a blog for my preservice elementary education class. It had several benefits: the blog served as a portal for all the individual student blogs accessible from a drop-down menu; it was free and public. Now, the free version can no longer be made public, limiting the purpose for having a blog.
I like to use tools my students can later use with their future
students. So, I'm looking for another free tool, which can be made public, is free, has an easy way to access individual blogs without creating a separate blog roll, and is not limited to K-12.
Weebly has an education account. You can also decide to moderate comments on the blogs, however it cannot be chosen for individual blogs but as a whole class. I then made all the students create their own blog rolls to connect all of the blogs together. You can also add a wide range of widgets and each student can customize their blog.
I'm a fan of tumblr, but, infortunately, it doesn't have great classroom/group support features.
On a colleage's advice, I started using http://www.glogster.com/ , which does have group support options and seems to be very interesting. I just started and am still in the lesson-planning stages of my glogster use, but it seems like a good resource and wanted to put it out there.
Also, wanted to share a tool i use to evaluate blog work by students (a really great online highlighter tool that allows you to share comments and collaborate in research/editorial work).