Twitter has adjusted the age restrictions for its Vine application after its controversial debut, during which the video-sharing service, like pretty much anything on the Internet, became overwhelmed with pornographic content almost instantaneously.

Originally rated for any user above the age of 12, Vine now has a 17+ rating on Apple’s (NASDAQ: AAPL) app store.

First released late last month, Vine quickly gained notoriety for the proliferation of explicit user-generated content marked with tags like “#sex” or “#porn.” While Vine’s terms of service stated that “users can report videos as inappropriate within the product if they believe the content to be sensitive or inappropriate (e.g. nudity, violence or medical procedures),” that didn’t stop one video titled “Dildoplay #nsfw #porn #nsfwvine” from making it into the app’s “editors’ picks” category, showing just how hard it is to regulate explicit content online. (A Twitter spokesperson later told Mashable that the “Dildoplay” selection was a “human error.”)

Apple, for its part, has given Twitter a fair amount of autonomy to resolve its so-called “porn problem” on its own terms -- an uncharacteristic sign of good faith from a company known for fiercely regulating all content made available on its App Store. Last year, Apple removed a similar video-sharing app called Viddy, because it had a porn problem of its own. And just last month (as Vine, no doubt, was already becoming flush with illicit material), Apple removed the photo-sharing app 500px due to the volume of nude pictures being circulated through the service.

Twitter first responded to the “#nsfw” content by blocking searches based on tags like “#nsfw” that would likely lead to porn. The new age rating adds another preventative layer over the largely unregulated user-generated content by warning people of “age-restricted material” contained within the app. In a move that’s sure to allay some parents’ concerns, the updated Vine app now says that users need to be over the age of 17 to download it.

How this new age restriction will be enforced, however, remains unclear. And as the murky waters of Internet pornography and social media regulation both show, Twitter may be facing an uphill battle. Countless users have realized that almost any website can be accessed by simply lying about their age, and more substantive legal restrictions such as the Children’s Online Privacy Protection Act, or COPPA, which mandates parental consent for Internet companies to collect personal data on children under the age of 13, can often have unintended consequences. A 2012 Consumer Reports survey, for instance, found that more than 5 million children under 13 still had active Facebook accounts despite COPPA’s prohibition, accounts that many created simply by lying about their age.

A study by computer scientists at the Polytechnic Institute of New York University published in November found that laws like COPPA can actually encourage minors to lie about their age in order to access the desired service.

“In a COPPA-less world, most kids would be honest about their age when creating accounts,” one of the study’s researchers told the New York Times last year. “They would then be treated as minors until they’re actually 18.”

Of course, Twitter’s Vine controversy is about access to sensitive content, not sensitive user data. But both problems illustrate the difficulty that Internet companies face once porn emerges. And what Vine's new age rating doesn't address is the question of how, exactly, Twitter is going to leverage a brand that's still packed with porn of one type or another for advertising revenue.