Twitter, Teaching, & Totalitarianism

I've always been a fan of technology and its potential to help people learn and collaborate.  I've been thinking for a while about social networking and education, and how it's probably not such a great idea for schools to simply block sites like Facebook & Twitter and pretend they don't exist, rather than teaching kids how to use them responsibly.  I'm hoping to do some collective tweeting with my classes in the fall as a way to model effective, responsible use of social media.  I've been on Tw