Why would we be threatened? It's a huge Internet and we support authors having autonomy to choose the right tools for them. You will notice that many, many writers here use both Medium and a newsletter service and we happily distribute these authors along with their links to these newsletter services. Each service fills a need in its own way and so it's better for writers to see them as complements and consider using multiple.

When it comes to SS specifically, we are so fundamentally different that I don't even see the comparison. Medium is a bundle and we specifically optimize for a type of writer who doesn't want to have to be a marketer to get read. That's basically the polar opposite of SS, where readers have to signup for multiple subscriptions and where SS rewards authors who are able to effectively market their own writing. (Effectively is hard and rare, as people often find out)