Substack's Secret Plan
Calling what Substack does "newsletters" is a very clever marketing gimmick. In truth, Substack is a nothing more and nothing less than a blogging platform—the next generation after blogspot and medium and the like.
Far and away the best technology for reading blogs is RSS1. But RSS never really got the widespread adoption it deserves. Perhaps you, like me, have an RSS reader stocked with the feeds of all your favorite blogs from across the blogosphere. But plenty of people don't, and they're missing out.
If you were to set out to solve this problem and bring the benefits of RSS to the masses, there are several ways you could go about it. Perhaps you would go out into the world and evangelize about the benefits of RSS. Feed readers are in fact pretty great, and you may well convince a handful of people to give them a try. But what you're going to get from that is at best a handful of converts, not widespread adoption.
On the other hand, Substack makes the bet that with a slight shift of frame, calling them "newsletters" not "blogs", you can trick people into converting their email inboxes into something very much resembling a feed reader! Perhaps setting up an actual feed reader is too much of an inconvenience, but people are already used to treating their email inboxes in more or less this way—a pile of entries, each marked read or unread, which you go through one by one and read, skip, or otherwise deal with each.
It is unfortunately true that an email inbox makes for a rather shoddy feed reader. Actual feed readers are much better suited for the task of reading blog posts—but for most people, the alternative to using their email inbox isn't to set up a real feed reader, it's to mostly not read blogs at all!
For those of us who do use RSS, Substack has us covered as well. Their website is a fully-featured blogging platform like any other, complete with real, honest-to-goodness RSS feeds. To anyone who uses a feed reader, reading posts on Substack is pretty much the same as posts on medium, blogspot, wordpress, tumblr, or any other blogging platform.
Feed readers really are an underappreciated technology—despite being one of the marvels of the modern internet, it's a staggeringly small percentage of the population that has even heard of feed readers (let alone actually using one.) Substack's one weird trick to bring this experience to a wider audience is quite clever, and I wish them success with it.
For the purposes of this post, the term "RSS" should be read to also include Atom feeds. Despite their technical differences, the user experience is identical. There is no particular need for the user of a feed reader to care about the distinction between the two.