This guy has a youtube channel and he analyzes cryptocurrencies.
He did announced that a lot of his content would go to his Stemmit account.
https://www.youtube.com/channel/UCpAXWMbMUv4P5R-15kHYFJw/feed

Even if we have the case that followers from his channel only came to Stemit to support him, I don't think he could have made all this money so quickly.
We have bigger Youtubers on the platform that would not make such amount of money. Talk to the guy, contact him. Let's figure this out.