There are over 1,000 instances and almost 30k communities at the moment (across all instances). https://lemmyverse.net
there are a few other nsfw-instances too.
I found Lemmy because of Reddit's nonsense and found communities to join in convo. I found Lemmy NSFW because it's on the internet and the internet's for porn.
I'm involved in a few NSFW software projects stashapp, xbvr, stashdb, pmvstash, theporndb and keeping an eye out for other projects.
I'd heard about lemmy and thought I might as well take a look.