I miss writing blog posts but don't miss spending an hour writing something that gets 10x fewer views than a tweet that took me 5 minutes to compose. Is this the problem Substack solves?

Haven’t checked it out in detail yet, but isn’t it just another domain other than your own, with all the problems that come with that, just like Medium?

It delivers your posts to subscribers via email. This seems like RSS all over again where there'll eventually be newsletter overload but the pioneers will build huge audiences before saturation.