[shiandow]

And when does the user decide? Must a platform do nothing to stimmy spam, or even illegal content to qualify as impartial?

I suppose the answer could be that only platforms that do indeed allow spam or worse are impartial, but that is a tricky position to be in.

[leogiertz]

The mechanism would be that if the user has chosen to follow an account then posts from that account falls under common carrier. If the platform choses to show you other posts then it's under their responsibility.