From the West Virginia site -
ClassChatter offers free blogging and web tools for teachers at all levels. It provides a private place for students and teachers to collaborate online. It is the only blogging site that I've found that doesn't require students to have an email address to have access. They do have a unique username and password assigned by the teacher. It is free and has no advertising. There are 3 types of blogs available. The first is a personal blog where kids log in and write their thoughts. They can be private or available for the class to read. In Topic blogs, the teacher posts a topic and students respond to it and each other. All students can see every posting. The teacher has the option of scrambling the student names so the children don't know who made which posting. The final type is an assignment blog. Students enter their response to the question or prompt and only the teacher can see it. The teacher can grade the assignment online and provide feedback to the student privately. ClassChatter also provides an email system that allows the teacher and student to communicate with each other. Students cannot email each other.
Student can log into this site from any computer with internet access. I often use it to extend discussions that we have started in class.