I would say every social media sites have fake accounts, they are created for various reasons. For example marketing, networking, and fun.
Sites like Steemit must have strict sign up process as well as detection technologies to catch fake users and bots and keep the system running.
There are many programs like Bubblews which were good but just because they were poor in recognizing fake people (spammers) got out of business.
Thanks for your valuable post @acidyo