Students and parents could use Weblogs for a way to communicate outside the classroom. If students are having trouble with a homework assignment, they could post their questions on the Weblog. Other students or the teacher could respond to the questions to try to help with the assignment. Parents could make postings to the Weblog to communicate with other parents.
I think that the Weblogs are great and would like to try to use them in my classroom one day. The only problem that I see would be in many of the students not having access to the internet at home and/or training the students and parents in how to use and make postings to the Weblog.