CNN has an in-depth look at the practice of “like farming,” wherein scammers sucker Facebook users into “liking” a page and then converting those likes into personal gains. In one example uncovered by CNN, scammers posted a photo of a young girl and urged users to like the photo as a means of encouraging the girl’s battle against cancer. As it turns out, not only was the photo six years old at the time it was posted, but no one – neither the girl nor her parents – ever posted the photo to Facebook. They had no idea it was being used at all, let alone for ill-gotten gain.

Scams like this are partially responsible for the otherwise inexplicable explosion of cloyingly sweet Facebook posts that can’t help but make a play for users’ emotions. Since Facebook recently changed their algorithm to prioritize more popular posts, scammers go for broke picking topics and causes that seem to be almost universally positive.

“The average user doesn’t know any better,” said Tim Senft, founder of Facecrooks.com, a website that monitors scams and other illegal or unethical behavior on Facebook. “I think their common sense tells them it’s not true, but in the back of their minds, they think ‘What if it is true? What does it hurt if I press like?’ or whatever.”

Scammers can take a couple of paths to profit from dishonestly earned Facebook likes. After creating a page for a cause or topic (like the aforementioned cancer patient, for instance), scammers can use the phony emotional ploy until they’ve gathered enough likes and comments to make the page rank highly in Facebook’s algorithm. Once they do that, they can sell access to the page for varying sums of money to other scammers or retailers. A user might “like” a page for a child needing a medical procedure, only to get directed to a page selling nicknacks the next day.

“The more likes and shares and comments and that sort of thing you have, the more likely it is to be seen by other people,” Senft said. “If they’re looking to sell the page in a black-hat forum somewhere, that’s what the value of the page is.”

Sometimes, the users themselves are the target of the scammers. Once they’ve “liked” a page, they’re vulnerable to phishing scams and malware thrust upon them by the scammers, usually in the form of bogus surveys or contests designed to mine personal data like passwords and credit card information. All of this for clicking an otherwise harmless Facebook button.

For their part, Facebook makes the effort to take down malicious content, though because of its sheer size it can sometimes take several flags before the post is deleted. Amanda Reith, mother of the daughter whose photo was used as part of a like farming scam, says she still sees her daughter’s photo pop up from time to time.

“What makes me truly angry, though, is knowing that they’re using it as an insidious way to make money,” Rieth said. “That’s not what her survival is about to us.”

Until Facebook is better equipped to more swiftly penalize scammers, the company advises users to employ old-fashioned common sense before “liking” a post.

“If it sounds too good to be true, don’t click on it,” Senft said. “If it’s something that’s obviously geared toward tugging on the heartstrings, check it out first. If you see a post that’s low quality and seems to be focused only on gaining traffic, hover over the top-right corner of the post and click the arrow to report it.”