I LOVE ALL THE FANNISH AUS FOR THIS. They are such a time capsule. And it can be MYSTIFYING. Before I got on tumblr, I was reading this fic where they were users on tumblr. Character A is angsting over Character B, so Character C sends B a message from A's account, and then closes the window. And A freaks out, going "what did you send?????"

And reader!Lanna, I was going "well, check your sent, idiot". LITTLE DID I KNOW, TUMBLR DOES NOT HAVE AN OUTBOX. Like, what.

So I think it's good we have a contemporaneous record of all the shit going on. :D

(I assume you've read the Sherlock version of this, whose title I can't recall right now? Theory of narrative causality? something like that?)