Dekita.org looks like a very interesting attempt at using blogs with learners of English. Plus, the site is beautifully designed. A quote from their About page:
Dekita.org also serves as a means for learners, educators, and other interested
people to locate student Web-publications and participate in the conversation.
As Dekita.org is a community of people dedicated to promoting
peer-to-peer communication in language learning, we welcome the contributions of
anyone who shares our enthusiasm for bringing together EFL /ESL learners with
people from all over the world in authentic and meaningful ways.