Twitter's iPhone video-snippet sharing service Vine had concerns about porn exposed on Monday after adult content was bared briefly in an "Editor's Picks" section. Twitter apologized for the mistake, blaming "human error" but providing little detail, and quickly removed the video. The globally popular one-to-many message sharing service last week launched Vine, a service that lets people share video snippets from iPhones or iPod touch devices. Perpetually looping video clips up to six seconds each can be shared using Vine or easily embedded in "tweets" fired off at Twitter. A free Vine application became available worldwide at Apple's App Store on Thursday. Reports soon surfaced of salacious snippets being found at Vine by people searching for such content. Eyes were on Apple, which has a history of booting from the App Store mini-programs that serve up adult content on its popular mobile gadgets. Twitter bought Vine, a startup based in New York, in October, prompting talk the messaging service intended to do for smartphone video what Instagram did for pictures. Twitter in December added Instagram-style smartphone photo sharing features after the Facebook-owned service made it impossible for Internet users to integrate its images into tweets. Previously, Instagram pictures shared in messages tweeted from smartphones could be viewed unaltered at Twitter. Facebook promptly blocked Vine users from being able to find friends at the world's leading social network, "clarifying" its platform policy in response to inquiries about the move. Platform operations director Justin Osofsky said in a blog post that apps aren't allowed to use the friend-finding feature if they "replicate our functionality or bootstrap their growth in a way that creates little value for people on Facebook." Osofsky did not directly refer to Vine or how the rule was applied to the service.