I think that was onlyfans, I could be wrong (because I cant be assed to actually look it up) but if I remember correctly they reverted their policy on nudity, but kept the ban on porn, to allow artists to continue to share their work.
IDK man, I've spent a lot more time on CuratedTumblr (r/ and c/) than on tumblr.com. I've been there only just long enough to come to the conclusion that I either don't get how you're supposed to use tumblr or that it's annoying to use (so. many. reblogs.).
and those other places no longer do porn, so anything that starts out as porn and somebody decides to turn into 'high' art can only really thrive here, or pornhub.
it's rare in a lot of places. most people are bad at art, and it's hard to get over that expressive hump to do nudes, and doing art while pushing past that is really difficult. fucking puritanism really fucks with all our sexy/body-horror art. also a staggering amount of children, which I'm sure is a coincidence.