I think that's a bit of a red-herring. I feel that increasingly the real difference is between 'end-user facing cloud products' (which essentially always means

I think that's a bit of a red-herring. I feel that increasingly the real difference is between 'end-user facing cloud products' (which essentially always means SaaS) and 'developer-facing cloud products' (which includes all your IaaS/PaaS/some-SaaS). Historically, the term for 'end-user facing cloud SaaS product' was 'a website'; we're just seeing tighter IAM integration in the enterprise space and more powerful products as a result of the increased capabilities of JS engines and better frameworks. The difference is basically "this is stuff developers used to build products" vs "this replaces a shrink-wrap product that would historically have been delivered to a user desktop".