That at some point, a character uses a device or machine to write (as in, technology for writing that exists in the story's world).

It doesn't have to be at all central to the plot, even is it just happens as an aside.

It interests me to see what people (who spend most of their time both writing and imagining the future) were thinking of when they imagined how people would write if they had the right technology.

Places where I've already seen such stuff are Asimov's Foundation and Empire, Philip K. Dick's The Penultimate Truth, Roald Dahl's The Great Automatic Grammatizator.