Well, I'm starting to see more web 2.0 sites getting blocked in my district. PB Wiki (which I used for a project with my kids) is not accessible. I'm looking at some other tools to see how to incorporate them in my classroom.
There are two tools I've seen recently that have different strengths (and weaknesses):
1. Tumblr.com: a REALLY simple an intuitive blog interface. I would LOVE an interface like this for student blogs.
2. 21 classes: Recommended by Will Richardson. The environment has all the controls I would want as an elementary teacher, but they have ads (one teacher was admonishing students to ignore ads on his site for site selling term papers), and the look is not as flexible as I would like (sidebar widgets, etc.) from what I can see.
I still love my edublog, but there is no garden wall there. I'm sure I could get it, if I paid, which is another thing to consider.