Steven Musil/CNET

After a dustup over pornography showing up on Vine, the Twitter-owned video-sharing app has added an age rating for possible adult content.

The app for iPhone and iPod Touch, which lets anyone create and share six-second clips, quickly became a popular venue for pornography after its release last month. Twitter responded by trying to make it harder for users to find the adult videos, blocking a number of porn-related search terms such as "#porn."

The microblogging site initially added a warning still to the beginning of videos in question that users would have to bypass to see the clip. As first noted by The Verge, Twitter released a new version today that requires users to confirm that they are at least 17 years of age; the previous version described itself as suitable for users 12 and older.

The app captured the controversy spotlight when a pornographic video briefly made Vine's "Editor Pick" list, further raising the question of whether the video-clip-sharing app has a porn problem.

However, the pop-up confirmation screen on version 1.0.5 appears to do little more to prevent access to questionable content than previous moves; children under the age of 17 lacking direct adult supervision can easily subvert this new obstacle to install the app.

CNET has contacted Twitter for comment on the new move and will update this report when we learn more.

The update follows similar moves by Tumblr and 500px, the latter of which was briefly removed from the Apple App Store presumably because of its photo-sharing capabilities, which might allow users to search for and find naked bodies.