One of the most obvious changes: it seems like almost every magazine uses Submittable now. I've submitted through Submittable before, but now just about every set of guidelines I read includes a link to that journal's Submittable page.
Submittable is a good system -- at least from the writer's side -- but it's strange to see it so commonplace now. I guess it works well for editors, or they wouldn't be turning to it in such high numbers. Are there any viable competitors to Submittable? I haven't seen any yet.