The major weakness I see is that many applications are blocked within school districts. Of course, many of the tools I have learned about are more unknown, and that is an advantage. Also, anyone can post anything, so students will have to be taught how to discern what is relevant.
I am very excited to use web 2.0 tools such as Zoho, Google docs, ning, blogging, engrade, etc. in the classroom. I am excited for my students. And an added bonus is when I get this all set up, is it makes life more easy on me as well!