Updated with industry benchmark petition conversion rates (4/11/12) and illustration by Lyla Duey (8/18/12).
For weeks, the only Trayvon Martin coverage I saw was on Twitter, where every progressive I knew had shared a link to the Change.org petition. Eventually, I saw more media attention around the story. This led me to form a hypothesis that people talking about the story online, and specifically, linking to the Change.org petition, kept the story alive long enough for the national media to pick up on it.
I looked into all of the data I could find, including some provided by Change.org, and found out that my hypothesis was incorrect. But the story of how Trayvon Martin became national news, weeks after his death, is still a revealing portrait of our media.