Alternative Title: "Tumblr will lose 80% of its visitors come December 18th" Another one: "Tumblr preparing to shut down"
This is exactly correct. Sure there are "clean" portions of Tumblr, but from what I can tell the real purpose is to host adult content. And there's nothing wrong with that! It's a fantastic magnet for eyes, with which to show ads. They're basically killing themselves with this.
Think of tumblr as nothing but a way to get pageviews for Cheerios and Volvo ads. It explains their decisions perfectly.