Cyberdash: Weblogs in the writing classroom:
"While weblogs are normally public, free tools such as Blogger can be used for private, expressive writing. Students need only choose "no" when Blogger asks if they want a public blogsite, keep their site's location on the web secret, and exchange the URL only with the teacher, resulting in a private electronic writing space where they can be free to express the personal. However, to use blogs merely as a tool for private journaling is to privilege our understanding of journals as private writing spaces without considering the benefits of weblogs as public writing."
There's a lot more here of interest to ELT teachers.