Instagram (231) > Tumblr (199, though I don't post on there anymore and most of my followers on there are inactive anyway) > Deviantart (89, though once again, most are dead accounts XD) > Twitter (83) > Pillowfort (69), > Webtoons (60) > Tapas (46) > ComicFury (19).
I wish I could make some sense out of all these numbers, but truth is... I really can't XD I mean, I'm not that active on Instagram AT ALL. Been on there for only a few months. Was VERY active during my first two weeks and got 200 followers during that time, then my numbers kinda stayed the same from there. Still, the followers I have on there are pretty active... something that never happened on Tumblr or Deviantart, where I've been for over a decade yet my art accounts were never noticed.
Twitter and Pillowfort do make a little more sense: I'm barely even active on Twitter and I only just revived the account for art-related stuff, while PF is where I've been consistently for about a year or so, but being still in beta, there aren't a whole lot of users there yet.
My webcomic is still new-ish (as in, I've been at it only for a few months)... yet for some reason I ended up getting more followers on Webtoon, which I do not promote AT ALL compared to Tapas or ComicFury, which is where the comic was posted first XD however, it's also true that currently Tapas is where I have the most interaction with my comic, so there's that