False flag propaganda and crisis actor conspiracies spread like an insidious digital weed. They grow stronger and longer, developing viral shoots that strangle the truth.
Just ask Emma MacDonald. She recently told her story to USA Today. Conspiracy theorists took a photo of McDonald crying at a vigil after the 2013 Boston marathon bombing. They pasted it beside other crying women after mass shootings in Newtown, Connecticut, Aurora, Colorado, and Parkland, Florida. Their conclusion, however improbable or implausible: All the women in the collage are white, thin and brunette and therefore must be the same person. A staged actress. A crisis actor.
McDonald, 25, said she knew it was coming — again — as soon as she heard about Parkland. "Enough is enough," she said. "This needs to go away." But it hasn't. And probably won't.
Just like a weed, even when these stories are chopped back with deletions and fact checks, they never really die. Each time, these self-perpetuating smears are the same — and you can blame the internet, in large part. It's almost impossible to control.
SEE MORE: Truthers: When Conspiracy Meets Reality
NBC News boils it down this way: "Unfounded information shows up on dubious sites, churns through the news aggregation site Reddit, and works its way into Facebook feeds — and to the mainstream media."
Along the way, Facebook and Twitter's algorithms fuel the spread. Recode explains that the algorithms are built to reward posts that receive lots of shares or comments, meaning "engagement." That leads to showing videos and other content to even more people — propagation.
Some people say there's an underlying human factor that keeps conspiracies alive. The author of "The United States of Paranoia" told The New York Times that conspiracies, no matter how crazy, can give meaning to a world that makes no sense.
Even cold, hard facts fail to derail conspiracies. Conspiracy theorists often say that attempts to debunk a conspiracy is actually proof of its existence.
Nothing seems to stop the spread once it takes root in the digital ecosystem. It spreads. It grows. From Sandy Hook to Parkland. Then it lies dormant, just waiting for the next mass shooting and friendly algorithm to start the life cycle again.