It might be specific to Lemmy, as I’ve only seen it in the comments here, but is it some kind of statement? It can’t possibly be easier than just writing “th”? And in many comments I see “th” and “þ” being used interchangeably.
It’s just that one guy i think
sp3ctr4l@lemmy.dbzer0.com 38 minutes ago
Because the thorn is an old timey English character, and some people are quirky / write in a stylized way_‽_