Beholden to Another Platform?

Clay Andres asked me via email if I had a brief response to Marco Arment's tweet about Medium:  

I wrote a brief reply — that grew and grew and grew into an essay about platform lock-in, intentions, and one's own needs:

[without your own domain] you're once again relying that a company will continue to exist in a form of your choosing, rather than its own

Clay asked permission to publish the whole dang thing, which I gladly gave: Why You Should Be Your Own Platform

(There's an irony that I'm letting someone else publish my words on their platform! Yes, I get that. But I own those words and will publish the essay here at some point later.)