I have flagged this as ridiculous clickbait. "I added a notification email to people who didn't finish signing up and made some extra money" is the gist of the article, and much more mundane.
"There is no program" --- it's an app, a bot, a micro-service, a nano-service, a REST Hook, a CLI, a Job, a miner --- "programs" are what gramps wrote!
It could also be that some or all of these 10% knew or expected that they would get a discount if they did this, in which case it would be a loss of (max) 1.5%.
A lot of people made a lot of money just researching key words, and building a product around that. I'm sure it's a quick flame, but cash can be made for sure.