If you’re a fan (or creator) of Tumblr porn-GIFs, today brings bad news: The Tumblr powers that be have decided that in furtherance of creating a “better, more positive Tumblr,” what is needed is a ban on adult content.

Starting December 17, two weeks from today, “posts that contain adult content will no longer be allowed on Tumblr,” according to a blog post attributed to Tumblr CEO Jeff D’Onofrio.

“We recognize Tumblr is also a place to speak freely about topics like art, sex positivity, your relationships, your sexuality, and your personal journey,” D’Onofrio wrote. “We want to make sure that we continue to foster this type of diversity of expression in the community, so our new policy strives to strike a balance.”

In his post, D’Onofrio acknowledges the balance he seeks can be a difficult one to strike.

“Filtering this type of content versus say, a political protest with nudity or the statue of David, is not simple at scale,” D’Onofrio conceded. “We’re relying on automated tools to identify adult content and humans to help train and keep our systems in check. We know there will be mistakes, but we’ve done our best to create and enforce a policy that acknowledges the breadth of expression we see in the community.”

The site’s new adult content policy, as stated within the revised Tumblr community guidelines, does provide some specificity about the kind of content which is now disallowed – but not without raising some head-scratching questions of its own.

“Don’t upload images, videos, or GIFs that show real-life human genitals or female-presenting nipples —this includes content that is so photorealistic that it could be mistaken for featuring real-life humans (nice try, though),” the revised guidelines state. “Certain types of artistic, educational, newsworthy, or political content featuring nudity are fine. Don’t upload any content, including images, videos, GIFs, or illustrations, that depicts sex acts. For more information about what this guideline prohibits and how to appeal decisions about adult content, check out our help desk.”

I suspect one of the first questions Tumblr users will have – one which has already been raised by Tracy Clark Flory in a post for Jezebel.com – is: “What does ‘female-presenting nipples’ mean, exactly?”

Given the recent removal of Tumblr from the App Store over a failure to filter out child pornography, it’s hard not to see a connection between that event and the platform’s new content policy, but D’Onofrio seemed to assert in his post that the two are not related.

“Let’s first be unequivocal about something that should not be confused with today’s policy change: posting anything that is harmful to minors, including child pornography, is abhorrent and has no place in our community,” D’Onofrio wrote. “We’ve always had and always will have a zero tolerance policy for this type of content.”

OK, so if the policy change isn’t related to the child porn mishap and resulting App Store ban, what did inspire the sudden change in policy? For starters, I suppose D’Onofrio would object to my description of it as “sudden,” since he presents it as the result of sustained, considered internal discussion.

“It is our continued, humble aspiration that Tumblr be a safe place for creative expression, self-discovery, and a deep sense of community,” D’Onofrio wrote. “As Tumblr continues to grow and evolve, and our understanding of our impact on our world becomes clearer, we have a responsibility to consider that impact across different age groups, demographics, cultures, and mindsets. We spent considerable time weighing the pros and cons of expression in the community that includes adult content. In doing so, it became clear that without this content we have the opportunity to create a place where more people feel comfortable expressing themselves.”

Sure – Tumblr users now will feel much more comfortable expressing themselves, just so long as their idea of self-expression doesn’t involve posting depictions of “real-life human genitals or female-presenting nipples” or anything so close to real life one might be tempted to conclude they’re real.

As D’Onofrio noted in his post, there’s “no shortage of sites on the internet that feature adult content.” Of course, there’s also no question Tumblr is significantly higher profile and more popular than the bulk of those sites – or that it has become a go-to for many people who are in search of “female-friendly” porn. Such folks simply will have to look elsewhere for their female-friendly porn GIF fix from now on, it appears.