Tangential remark: substack is becoming as annoying as medium now. Especially on mobile. One big popup asking to register. One constant toolbar asking to register. One constant toolbar asking to install the app. Many interruptions in the main text for subscribe and share reminders.
That didn't take long for it to go bad :( I only heard about substack about a year ago when Snowden's blog was in the news and they were still saying they'd keep it clean (like medium promised initially as well). And it was pretty clean then.
I was even thinking of putting my own blog there (which is free and unmonetized) but no.
On medium it's become so bad now that I don't even open their links anymore unless it's really something I am so curious about I'm willing to put up with the experience. I really hope substack doesn't go the same way.
Sure they have to make money but alienating your userbase doesn't seem a great way to do so in the long term.