@JohnPhilpin Sounds like a nifty feature! One might have to work around some Hugo-specific quirks, but a plug-in could provide something close to the glossary thing in Drummer.
If I understand it correctly, it's a text substitution feature. You define in your glossary that ;) should render as 😉 and Emoji as <a href="http://en.wikipedia.org/wiki/Emoji">Emoji</a> and so on.
Definitely doable! You just have to find a developer that wants that feature bad enough in Hugo/Micro.blog. 😊
Until then, an alternative is using text-expanding software like TextExpander or the rudimentary Text Replacements that's built-in with Apple's operating systems. In combination with Micro.blog's search and replace feature, to add (or redefine) links/definitions to words in old blog posts.