The word "truth" is in the name we've given them, but the view of reality that so-called truthers have is typically anything but truthful.
There's a variety of denials espoused by some, from trying to prove that the Holocaust never happened to believing that the massacre of 20 children and 6 adults at Sandy Hook Elementary School was a hoax. A series of recent confrontations by Sandy Hook truthers has brought their presence and perceived causes to the forefront, as well as concerns about protecting people from them, in some cases.
For most of the world, the devastation of the 9/11 attacks can never be forgotten, along with other tragedies, like Sandy Hook. The images of the grief are seemingly etched in the collective psyche.
However, for some people on the fringe, those images exist to be refuted. Videos like "We Have to Talk About Sandy Hook," which attempts to refute the existence of the massacre, and "Loose Change," which insists that 9/11 was engineered by the government, have been produced by truther groups.
Some of their creators, members and followers have gone beyond denial and have attempted to personally challenge people affected by tragedies by creating unwelcome situations.
Recently, Scarlett Lewis, the mother of a murdered Sandy Hook first grader, released a book about her journey of grieving, titled "Nurturing Healing Love." So many truthers answered an online call to "truth bomb" reviews of the book on Amazon by giving it negative reviews that they brought its rating rating down to 2.1 stars out of 5.
Also, over last weekend, Matthew Mills, 32, showed up at a 5K run in Connecticut to benefit the foundation of the family of Vicky Soto, a teacher who lost her life protecting her first graders in Sandy Hook Elementary.
Mills was arrested after he angrily confronted Soto's sister, seeking information that may deny the teacher's existence.
Mills, who lives in Brooklyn, also briefly interrupted the post-game news conference at the Super Bowl at MetLife Stadium two years ago, where he made a statement accusing the government of engineering 9/11.
Psychologist Jeff Gardere, PhD, discussed in an interview what can cause denial by truthers as well as the sometimes violent behavior that can accompany it.
"In your mind, you're an individual," Gardere said about the mindset and practices of many truthers who perpetuate conspiracy theories, "and this is how you prove it, even if it's inappropriate."
"Most conspiracy theorists come in groups. They're part of a club. They feed one another this sort of paranoia," Gardere said.
That group mindset gets strengthened online, according to social media expert Peter Shankman. He said that truthers are looking for other people who share their extremely contrarian viewpoints. Being active online, he told PIX11 News, is "an incredibly easy way to do that."
Shankman wrote extensively about the power of social media, and is a sought after speaker worldwide about its capabilities. He said that while many people benefit from the reach of social media, it is particularly effective at bringing together individuals who may otherwise be spread far apart from one another.
"If this is something we believe in," Shankman said about online groups, they're drawn together, no matter who or where they are. But typically, said Shankman, those groups share fairly benign, uncontroversial interests. Often, the less mainstream the interest, the fewer the followers.
That's where creating online communities becomes key to the cause.
"[It's] much easier to find the fringe of society, thanks to the Internet," Shankman said.