Are you new to the Internet? F4F or buying followers is a tactic that probably started at least as long ago as 2009 - when the idea of earning a passive income (money in your sleep for doing less than nothing) became popular and launched the "careers" of numerous bloggers.

But yes, it became more of a "thing" on Medium when they started awarding sign-on bonuses and requiring a minimum entry point of 100 followers for the MMP - a stupid move from Ev Williams, who, as founder of Blogger for crying out loud, should have KNOWN was a disaster in the making. But maybe it's just his MMO (make money in your sleep for doing less than nothing online) strategy. I really thought he was better than that (still do, but this is a disaster, isn't it?)