It's the simple meme that's taking over your social media feeds: the "10 Year Challenge," where users upload side-by-side photos of themselves from a decade ago and now.

But it might not be so simple.

Facebook on Wednesday distanced itself from the "10 Year Challenge" after an article set off speculation that the social media giant could be secretly mining data from the photos to improve its facial recognition algorithms. It's a scenario that those who have studied social media companies don't rule out, despite Facebook's denials.

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The photo challenge gives Facebook "a perfect storm for machine learning," said Amy Webb, a professor at NYU Stern School of Business with an upcoming book about how artificial intelligence can manipulate humans.

"It presented Facebook with a terrified opportunity to learn, to train their systems to better recognize small changes" in users' appearances, she told CBS News.

The "10 Year Challenge" popped up last week and across Facebook, Instagram (which is owned by Facebook) and Twitter millions of people have participated. The challenge generated 5.2 million engagements on Facebook in just three days, according to the social media monitoring tool Talkwalker. It was the latest in a constant stream of social media crazes — like the "Bird Box" challenge and Top Nine photo collage — that enticed users to join in with little concern for safety and privacy. There are also viral hashtags like #MyFirstConcertWas, which get users to reveal answers to popular security questions.

Speculation about the meme's ulterior motive flared up after Wired writer Kate O'Neill published an op-ed suggesting it wasn't just harmless fun.

O'Neill pointed out that the viral challenge has filled Facebook with labeled, side-by-side user photos taken within a fixed period of time. That's different, and easier to analyze, than the years of photos that users have already uploaded in no particular order. It's also more useful for technology that's trying to capture how people look and how they age.

She warned of "fraught consequences" that could come from this data, such as insurance companies kicking up coverage costs for people who seem to be aging quickly. (There has been no evidence so far that this is happening.)

Facebook issued a statement saying it had no role in starting the challenge and saw no benefit in it.

"This is a user-generated meme that went viral on its own. Facebook did not start this trend, and the meme uses photos that already exist on Facebook," the company said. "Facebook gains nothing from this meme (besides reminding us of the questionable fashion trends of 2009). As a reminder, Facebook users can choose to turn facial recognition on or off at any time."

But even if Facebook didn't initiate the challenge, it has been using facial recognition intelligence for years to recognize users and people they are pictured with. It is also rolling out new products that rely on artificial intelligence, such as Portal, a video chat screen with a camera that can follow you around a room and automatically focus on your face.

The "10 Year Challenge" comes about a year after a similar effort from Google, one of Facebook's biggest competitors. Google's Arts & Culture app matches selfies with works of art that resemble the user. The app uses facial recognition algorithms to create side-by-side comparisons after users upload a photo.

Whatever Facebook gets out of the "10 Year Challenge," Barr said it's significant that people questioned its motive in the first place. After an avalanche of Facebook privacy scandals and data breaches in the past two years, now even a meme seems suspect.

"It's good that finally, even though it took a couple days, eventually the conversation (began) of, 'Wait a minute, did we just play into the hands of the tech giants again?'" Barr said. "At least that was part of the conversation."

Dan Patterson contributed to this report.