Twitter announced a new policy Thursday that prohibits sexually explicit content from being posted on its video-sharing app, Vine.

The microblogging service announced the update to its terms of service in a company blog post that said that the vast majority of its users would not be affected by the change.

"For more than 99 percent of our users, this doesn't really change anything," the post reads. "For the rest: we don't have a problem with explicit sexual content on the Internet -- we just prefer not to be the source of it."

The smartphone app, which lets anyone create and share six-second clips, became a popular venue for male genitalia and pornographic movies taped off TVs and laptops soon after its release in January 2013. Concern over sexually explicit content on the service intensified after a pornographic video briefly made Vine's "Editor's Pick" list.

Twitter initially responded to the issue by trying to make it more difficult to locate sexually explicit videos on the service by blocking porn-related search terms such as #porn. After adding a warning message to the beginning of questionable videos that users would have to bypass before they could see the clips, Twitter released an update that required users to confirm that they were at least 17 years of age. The previous version described itself as suitable for users 12 and older.

While the new policy prohibits images that depict sex acts, sexually provocative nudity, and sexual arousal, Twitter says it's not banning all nudity from the service. Depictions of nudity or partial nudity posted for documentary, educational, or artistic purposes will still be allowed.