The anniversary of the 9/11 attacks dominated social media from September 12-16, registering as the No. 1 subject on blogs and Twitter and among the top YouTube videos, according to the New Media Index from the Pew Research Center's Project for Excellence in Journalism.
And the way the story played out last week out helps illustrate the different functions of the three online platforms.
The conversation on blogs, often a forum for debate, was passionate and ideological in response to columns criticizing how Americans were treating the anniversary of the attacks.
Read the full report, Social Media Users Remember and Debate 9/11, on the Pew Research Center's Project for Excellence in Journalism Web site.