An anonymous reader writes: It started with the Boston marathon bombing, four years ago. University of Washington professor Kate Starbird was sifting through thousands of tweets sent in the aftermath and noticed something strange. Too strange for a university professor to take seriously. "There was a significant volume of social-media traffic that blamed the Navy SEALs for the bombing," Starbird told me the other day in her office. "It was real tinfoil-hat stuff. So we ignored it." Same thing after the mass shooting that killed nine at Umpqua Community College in Oregon: a burst of social-media activity calling the massacre a fake, a stage play by "crisis actors" for political purposes. "After every mass shooting, dozens of them, there would be these strange clusters of activity," Starbird says. "It was so fringe we kind of laughed at it. "That was a terrible mistake. We should have been studying it." Starbird argues in a new paper, set to be presented at a computational social-science conference in May, that these "strange clusters" of wild conspiracy talk, when mapped, point to an emerging alternative media ecosystem on the web of surprising power and reach. There are dozens of conspiracy-propagating websites such as beforeitsnews.com, nodisinfo.com and veteranstoday.com. Starbird cataloged 81 of them, linked through a huge community of interest connected by shared followers on Twitter, with many of the tweets replicated by automated bots. Starbird is in the UW's Department of Human Centered Design & Engineering -- the study of the ways people and technology interact. Her team analyzed 58 million tweets sent after mass shootings during a 10-month period. They searched for terms such as "false flag" and "crisis actor," web slang meaning a shooting is not what the government or the traditional media is reporting it to be. Then she analyzed the content of each site to try to answer the question: Just what is this alternative media ecosystem saying? Starbird is publishing her paper as a sort of warning. The information networks we've built are almost perfectly designed to exploit psychological vulnerabilities to rumor. "Your brain tells you 'Hey, I got this from three different sources,'" Starbird says. "But you don't realize it all traces back to the same place, and might have even reached you via bots posing as real people. If we think of this as a virus, I wouldn't know how to vaccinate for it." The report goes on to say that "Starbird says she's concluded, provocatively, that we may be headed toward 'the menace of unreality -- which is that nobody believes anything anymore.'"