Isn't Tumblr just a shadow of it's former self because Verizon bought it and killed the NSFW accounts?
Checking Wikipedia, yeah, Yahoo owned it. Verizon bought Yahoo.
~ Yahoo bought Tumblr for $1.1 billion in 2013
~ Verizon bought Yahoo (which was big and bloated) for $4.83 billion (including Tumblr) in 2017.
~ Automattic (the guys that own Wordpress) bought Tumblr for less than $3 million from Verizon in 2019.
We don't quite have enough information to make this a cautionary tale, but it sure smacks of being a cautionary tale.
Edit: Fixed formatting