But isn't Tumblr userbase mainly teens and their subcultures? What's the value of not having ads, sponsor and astroturfing, if there's not relevant or interesting community to join to begin with?
“All tumblr users are either too young for tumblr or too old for tumblr” - “tumblr teen” argumate (argumate is certainly not a teenager (I think he is probably like, almost 40?) but some news article referred to him as such at one point)
I wouldn’t say there’s nothing interesting on tumblr.
Like, there’s nostalgebraist’s writing on machine learning,
Also other people posting some math content.
It is a social blogging site. People write blogs there.
Just because a platform is not relevant or interesting to you or your circles doesn’t mean it has no value to others. Lots of people got a lot of value out of using Tumblr. When Facebook was limited to people you know in real life, Tumblr allowed for anonymity and making friends with people with similar experiences.