We might be overstating Twitter's role in this situation. Because we are receiving so many good reports via Twitter, those of us who aren't in Iran might be committing a type of spotlight fallacy by believing that Twitter is having a large effect on the events themselves.
A while back Vancouver Film School (VFS) released a short-film on how Iran embraces new media, namely the web. The piece is titled "Iran: A Nation of Bloggers", can be watched at http://www.youtube.com/watch?v=MChlT0GvFPM . With about 100000 (one hundred thousand) actively maintained blogs, I can imagine Twitter indeed does play an important role there.
