Twitter's Vine hits top spot among free App Store apps

Vine co-founder Rus Yusupov announced the achievement on Monday in a tweet from his personal account. In the two and a half months since Vine's release, the video clip sharing app has steadily climbed the App Store charts. Along the way, the app has seen its share of controversy.

Shortly after its release, users began posting pornographic material to the service, a development worsened by the inadvertent inclusion of some of that material as an "Editor's Pick" on the service. With observers commenting that Vine apparently had a "porn problem," Apple soon removed the app from its Editors' Choice group of apps and took it out of the Featured section of the App Store as well.

Soon after, Vine saw an update that marked it with a 17+ age rating due to the possibility of users encountering adult content. That rating remains to this day, but it hasn't stopped Vine from shooting to the top of the free app charts.

Part of the app's success stems from deep integration with Twitter, the hugely popular microblogging service. Twitter users not familiar with Vine will still see short clips from the app showing up in their Twitter feeds. The app also allows for sharing to Twitter rival Facebook, further spreading awareness of Vine.