Golnaz Esfandiari sketches them:
There was no Twitter Revolution inside Iran. As Mehdi Yahyanejad, the manager of "Balatarin," one of the Internet's most popular Farsi-language websites, told the Washington Post last June, Twitter's impact inside Iran is nil. "Here [in the United States], there is lots of buzz," he said. "But once you look, you see most of it are Americans tweeting among themselves."
A number of opposition activists have told me they used text messages, email, and blog posts to publicize protest actions. However, good old-fashioned word of mouth was by far the most influential medium used to shape the postelection opposition activity. There is still a lively discussion happening on Facebook about how the activists spread information, but Twitter was definitely not a major communications tool for activists on the ground in Iran.