https://www.theverge.com/2018/12/3/1...-why-safe-mode
In order to try to eradicate illegal and undesirable content from Tumblr, the site will begin banning graphic adult content. Banned material includes pictures, videos, and GIFs of genitalia, nipples (female only), and images of sex acts. Text will still be allowed, as will "art that features nudity" (whatever that means).
A whole lot of sex workers' blogs will take a hit. I know a lot of providers use Tumblr as their main advertising/web site.
And in the end this will have very little chance of impacting the actual target of this ban. People who look for illegal and undesirable material on Tumbler aren't using it as a source for that material. It is a "beacon" that signals content located on other sites. Guys post illegal content that is re-blogged, but when the content is deleted the links to the other blogs remain as breadcrumbs to help people find other repositories of illegal material. Blocking all adult material won't impact the illegal stuff, but will annoy people who want to share legitimate erotica.