Well, maybe "invention" wasn't the right word, but it was a tremendous scientific breakthrough nonetheless. It was a complex computer algorithm, enhanced by nanowave technology - a code that could be slipped into an existing program, completely unnoticed by both its users and developers. John had spent months developing it, and now he knew the perfect way to deploy it.
Social media was sure to be the future of the economy - a whole ecosystem had sprung up of beautiful people getting paid to do basically nothing except post flattering pictures and videos of themselves. The more they posted, the more followers they'd get - and then the endorsements would come. Clothes, cosmetics, diet supplements, energy drinks; you name it these people were hawking it. And making good money, too. John certainly didn't have the looks or the social cachet for that, but that was where his algorithm came in.
All he had to do was integrate his code into some influencer's account. Any time that user made a post, the algorithm would harness the nanowaves from the server in John's basement lab. Those nanowaves would then be beamed to the devices of anyone looking at the influencer's post. Anyone viewing the post would be compelled to emulate the post's content - a hairstyle, an outfit, a makeup look, even an exercise or dance routine. But most importantly, they'd be compelled to buy whatever the influencer might be selling (and John's code ensured he'd get a cut of every sale).
Every post would compel one's followers to tailor their life to be more like the influencer - and the nanowaves would help accommodate that, shifting reality slightly and making their changing behavior seem mostly normal to their friends and family. And eventually people who were being influenced would become influencers themselves. They would begin posting content just like their influencer, which would lead to more followers, and more sales! It was as good as printing money!
But now it was time for some beta testing. Sure, John could unleash the full power of the algorithm, but he had to make absolutely sure there were no bugs in the nanowaves, otherwise it could cause some serious problems with the fabric of reality. As much as he wanted to start amassing a fortune, he knew he'd have to start small. He could adjust the code slightly to only influence one person at first, then he could track how much and how quickly that person was influenced. First, he scanned through Peepagram (the most popular photo and video social media app, of course) to find the perfect influencer. This person would become the template. Then all he had to do was find some unsuspecting target to be influenced. All he'd have to do is get that person to look at the influencer's post, and watch the changes unfold.
Note: I hope this isn't too convoluted. Basically the "target" should start to become more like the "influencer" based on the posts they look at. How that unfolds is up to you ;)