> I never really see people use them purely to replace words one-for-one.

This article does that. Here it might be more often than the author would normally do, but I've seen things like that non-ironically.

> To stay relevant in the age of social media you had to support emoji or you were in the .

EDIT: HN stripped the emoji. The end of that sentence was "or you were :skull: in the :droplet:", read as "or you were dead in the water".