I think the tea party has been driven mostly by traditional media, namely talk radio and cable news (Rick Santelli's original rant was broadcast on CNBC). Of course there has been a lot of online organization but I think the main promotion occurred over traditional channels.
Santelli's rant occurred on CNBC, but it was watched and shared on YouTube. Mainstream media totally missed the Tea Party movement, which got rolling during the bailouts in late 2008 but wasn't really covered until after Scott Brown's surprise election win in the winter of 2010.
