You have held firm so far on not acquiescing to cancel culture. But I imagine Apple will start demanding you censor content available through the Substack app, like they have with Parler and others. What will you do in response?
I think the Substack model gives us a bunch of advantages here: readers are choosing to subscribe to writers they trust, and who they then have a direct relationship with. I don't think that Apple is likely to try to police that too heavily, and if they do there is always web and email that exists as a fallback.
As someone who uses and loves substack precisely because of its censorship resistance, this sounds like wishful thinking at best. Even if substack is primarily web based, introducing a dependency on the ever-changing Apple content policing system is a potential conflict of interest.
A cynical take is that smaller platforms compete early by allowing more speech, only to close it down when they become bigger and tied up in corporate relationships.
How do you remain independent as you grow?
I.e. I think Substack's content is less likely to violate any rules (though I can only speak with so much confidence, having not read every article on Substack).
We don’t allow content that promotes harmful or illegal activities, including material that advocates, threatens, or shows you causing harm to yourself, other people, or animals.
...
Nudity, porn, erotica
We don’t allow porn or sexually exploitative content on Substack. We do allow depictions of nudity for artistic, journalistic, or related purposes, as well as erotic literature. However, we may hide this content from Substack’s discovery features, including search and on Substack.com.
Plenty of censorship in those paragraphs to any free speech absolutist who strives for ideological consistency. They're "cancelling" enormous amounts of what many consider free expression.