Here’s an interesting change: Tumblr’s iOS application just received an update which now lets you turn on or off adult-oriented, NSFW search results just by toggling a switch in iOS’s Settings. That’s right: you can now switch on or off the Tumblr porn with ease. Weirder still, Tumblr’s note about the change in the App Store update text says this was implemented “per Apple’s content guidelines.”

Why is that weird?

Because Apple’s developer guidelines – at least today – explicitly tell app developers not to do this sort of thing.

Above: Tumblr’s iOS app update text 

While Apple has never permitted explicit apps whose sole purpose is to serve pornography, it long ago carved out an exception for social networks hosting user-generated content, provided they agreed to filter and hide the NSFW content by default.

This is an issue that greatly impacts Tumblr, given that its blogging network is actually composed of a lot of porn. In fact, according to website analytics service SimilarWeb, “adult” content is the top category that drives direct clicks to Tumblr’s desktop site, accounting for 20.53% of clicks, compared with the next-largest referring category, “books and literature,” which drove just 7.61% of clicks.

Above: Tumblr’s new porn toggle

Tumblr has always had NSFW content, saying that its policy about this sort of material is a “live-and-let-live” kind of thing, but it draws the line at actually hosting sexually explicit videos. (Embed them, it says.)

To be allowed into the iTunes App Store, Tumblr has had to filter out and hide this content in its iOS app by default. There’s a loophole, though – as I’m sure many of you know.

According to Apple’s App Store Review Guidelines, apps like Tumblr are allowed to show the NSFW content if the user turns the setting on via the service’s website.

Here’s the full text, per Apple’s App Store Review Guidelines, about how this system is supposed to work, emphasis ours:

Apps with user-generated content or services that end up being used primarily for pornographic content, objectification of real people (e.g. “hot-or-not” voting), making physical threats, or bullying do not belong on the App Store and may be removed without notice. If your app includes user-generated content from a web-based service, it may display incidental mature “NSFW” content, provided that the content is hidden by default and only displayed when the user turns it on via your website.

Tumblr clearly fits in that latter category of apps that display “incidental mature NSFW content,” but it’s now being told to put a toggle right in iOS’s Settings?

Hmmm. 

The most logical explanation for this sort of change is that Apple will allow this setting to be locked down via its parental controls at some point. That’s not the case right now, though.

Under “Settings” –> “General” –> “Restrictions,” you can block the kids from using Apple’s built-in apps, block app downloads, and can block apps based on their current rating. (Tumblr is rated 17+, for example). However, there is not a way to force something like a Safe Search toggle switch to remain on.

Above: iOS 10’s Restrictions screen

It’s possible that Apple will roll out improved parental controls in the next version of its mobile operating system, iOS 11, which is expected to be announced at WWDC this summer. Perhaps it directed Tumblr to implement this setting in preparation of that change. (And maybe Apple didn’t expect Tumblr to code the fix so quickly…or call it out in the app’s update text!)

Other apps where adult content could be a concern – like Google, Twitter, Reddit, Flickr, 500px, and Pinterest – don’t currently offer this sort of toggle switch in the iOS Settings, even though they may offer content filtering mechanisms of their own in their apps or on their websites.

Of course, another explanation is that Apple is just chilling out about NSFW content in general, but that seems far less likely given the company’s historical position on a being a family-friendly App Store.

“Folks who want porn can buy an Android phone,” Steve Jobs famously said.

Apple has not responded to requests for comment about the matter. Tumblr declined to comment.

Disclosure: Yahoo owns Tumblr, and is in the process of being acquired by Verizon; Verizon owns TechCrunch parent company AOL.