These posts rely on people thinking a simple share or tag won't hurt anyone even if it's fake. But the more people who share them, the more chance someone has of being sucked in.
Then there are the really dangerous ones who spout misinformation - "Grandmother Mary cured her cancer by only drinking the juice of boiled radishes for six weeks!"
Dangerous because people could delay lifesaving treatment in hopes of a miracle cure that turns out to be snake oil.
There's a subset of society who are more likely to fall for fake news and conspiracy theories.
As published in the British Psychological Society Research Digest: "It is feelings of powerlessness that is one of the things that often attracts people to conspiracy theories."
In other words, if you've been diagnosed with cancer and feeling helpless, you are more likely to fall victim to quack cures because you're searching for a way to take back control.
The moral of the story is, no matter how much you want to believe something is true, you should always check the facts.
Look for evidence from multiple reputable sources, or you can look at the hugely reliable fact-checking website Snopes, which dedicates huge resources to verifying information in rumours and sketchy claims.
Just remember - if in doubt, check it out.
Fact checking isn't just for April Fools' Day.
