I see. I had no idea that the blockchain allowed anyone to access and redistribute content in this way. Thank you for explaining.
Does this mean that anyone who sees my content on these other platforms can then vote for, etc. it there, too? How do I access these accounts? How do these other sites differ from Steemit?

I'm dissatisfied with Steemit - it does not do what it was promoted as doing, which is to say it doesn't allow authors to earn based on their worth. People earn by joining voting blocs and they can post utter crap and earn money. I work hard and earn pretty much nothing.
Thanks.