That's what I was going to say but better and more detailed. I think most of Tumblr's core has migrated to IG, Snapchat, and some of those others I'm not hip to. I always saw Tumblr as a simplified MySpace but it had much of that same appeal - you could customize your templates and basically turn it into a teenager's room covered with posters and crap if that's what you wanted. On mobile all that is wasted - what looks impressive on desktop gets lost on mobile. So they're going the way of MySpace now.