Hey, neat! Thank you! It's an "imagination engine" - the original mod @Arotrios kbin.social wrote a detailed description here.

I never really fully got my head around it but it seems to be a combination of art, poetry, music, cinema, mythology, etc and a lot of the posts in it bounce off other posts in it.

I don't think Lemmy uses hashtags but it still gives you an idea:
#13thfloor #cinemainsomnia #oddradio #poetry #magic #imagination #storytelling #music #history #mythology #archaelogy #art #fiction #writing #environment #physics #magick #cinema #books #literature