Twitter might not be as important to the US as it is to a lot of other countries. A lot of content that is censored or blocked in countries by restrictive regimes rises on twitter organically. I think it plays a big role in dissemination of information from reporters etc. Take Pakistan for instance currently all the private channels are completely controlled by government it under quasi martial law. But because of twitter people are aware of 1000s of political prisoners including women and children, disappearances of reporters, harassment and threats by law enforcement to protestor families and relatives to control the protestors.