When Wikipedia got started, one of their early crises / edit wars had to do with people wanting very strongly to describe Tlön from an in-universe perspective. (People who've read the story will understand why!)

A kind of analogous later Wikipedia edit war had to do with whether the article about Gadsby (the lipographic novel that doesn't use the letter E) should be written with the same constraint as the novel itself, and also whether the article on E-Prime (an approach to writing English without using the verb "to be") should be written in E-Prime or not. But I feel like the Tlön issue was the granddaddy of all of these controversies.

TUOT is great.

The one that has stuck with me is "The Immortal"