In a controversial move, social media website Tumblr has announced it will start removing all pornography and explicit content on December 17th, 2018 and subsequently ban adult content going forward.

The ban comes three weeks after Apple removed the Tumblr app from its iOS app store after it was discovered underaged content was slipping through an 'industry database of child sexual abuse material,' but it's unclear if the move to ban all adult content is due to Apple's decision.

For context of how much adult content there is on Tumblr, former Tumblr CEO David Karp said in June 2012 that roughly two to four percent of the content on Tumblr was related to pornography. A year later, in May 2013, web analytics firm SimilarGroup came out with its own analysis claiming 22,775 of the 200,000 most-visited Tumblr domains were pornographic in nature — roughly 11.4 percent. The discrepancies between those two statistics is stark, but regardless of how it's looked at, there's a great deal of adult content floating around the social network with more than 100-million blogs.

'Posts that contain adult content will no longer be allowed on Tumblr, and we’ve updated our Community Guidelines to reflect this policy change,' says Tumblr CEO Jeff D'Onofrio in a blog post on the Staff Tumblr. He goes on to say 'Bottom line: There are no shortage of sites on the internet that feature adult content [...] We will leave it to them and focus our efforts on creating the most welcoming environment possible for our community.'

Where things get interesting is how Tumblr is defining adult content. On Tumblr's Help Center page, it defines it as follows:

Adult content primarily includes photos, videos, or GIFs that show real-life human genitals or female-presenting nipples, and any content—including photos, videos, GIFs and illustrations—that depicts sex acts.

Tumblr goes on to say on the same page what is allowed, which reads as follows:

Examples of exceptions that are still permitted are exposed female-presenting nipples in connection with breastfeeding, birth or after-birth moments, and health-related situations, such as post-mastectomy or gender confirmation surgery. Written content such as erotica, nudity related to political or newsworthy speech, and nudity found in art, such as sculptures and illustrations, are also stuff that can be freely posted on Tumblr.

In terms of photography, it appears as though nearly all nude photography will be removed and banned, regardless of how tasteful it is or isn't. That is, unless it's a male nipple or pertains to the other exceptions mentioned above.

Tumblr has started flagging content as inappropriate already and will continue to do so. In the event a piece of content was flagged unnecessarily, something that's already happening, Tumblr has an appeal button alongside the post that can be used to protest the flag.