[lmm]

> But if you say your system uses "Markdown" then that's zero help for someone who wants to submit to you a complicated Markdown document for processing.

This "Standard" makes things even worse. There are plenty of sites already on the internet that say they accept "Markdown", and that meant something: that it implements Gruber's formatting, and perhaps some extensions (and sites with extensions are normally clear about the fact that they're extensions, e.g. "Github-flavoured Markdown"). Now people will see a site that accepts "Markdown", expect it to support a feature from "Standard Markdown", and get angry when it doesn't.