I believe Tumblr is an 18+ website, on top of that Tumblr accepts posts in a lot of different formats. I would say you need to use it to understand it best. Tumbles audience or users have have been less interactive over the last few years as other blogging sites take over.
However I have found it to be great against my SEO strategy and it brings quite a large amount of traffic to my websites. http://mygaysites.com/gay-tumblr-porn-sites It’s very similar to google plus in the way it works, however the content from its users is very different compared to google plus.
I believe Tumblr has something very different regarding blogging, and Yahoo is not building out this capability, and that is it could be a massive competitor to WordPress. Because;
It’s an easier learning curve
It’s already has templates that can make your blog look like a real website
You can easily add an ecommerce function
Tumblr has all the makings to be one of the biggest platforms on the internet but it’s not promoting these features.