This is a serious question: in what sense does Substack compete with Twitter? The former (to my understanding) is a Medium-style blog host with some monetization functionality; the latter is a social network that was originally (but is no longer) advertised as microblogging.
(This is before other, more basic criticisms of Substack, like that it seems to have really only had success with a small group of bloggers who I would pay money not to be exposed to.)
(This is before other, more basic criticisms of Substack, like that it seems to have really only had success with a small group of bloggers who I would pay money not to be exposed to.)