In less than a year, Popcorn Time has become one of the most popular services to torrent pirated media content online. The slick grid interface looks similar to that of Netflix or Hulu, making the service look more legitimate and easier to navigate to find a TV show or movie. The program is actually an index of other BitTorrent sites. Popcorn Time’s popularity has been growing in the U.S. and abroad, especially in countries where streaming services are less established.

Popcorn Time’s growth has video streaming services and movie studios worried. Popcorn Time grew 336 percent from July to January in the U.S., according to Bloomberg. The service now accounts for one-ninth of the country’s torrent traffic. In the Netherlands, Italy, Portugal, and Spain, Popcorn Time is being searched via Google at the same rate as Netflix or HBO.

The torrenting site is so popular because it looks so legitimate. Some users didn’t even know that they were torrenting content because the clean, grid-layout looks just any other online video site. Touting minimal ads, there are versions for desktops, tablets, and smartphones.

Popcorn Time was launched last March by a group of anonymous developers. The creators shut down the site just a few weeks later, but the open-source code made it easy for other developers to recreate the platform. The developers of these spin-off sites say that they aren’t breaking any laws because their sites do not host the illicit content, but that defense might not hold up in court.

The Motion Picture Association of America (MPAA) has lobbied non-profit Web groups and Web hosting companies to take down the sites with popular versions of Popcorn Time. The organization may also have been involved with the takedown of the original Popcorn Time site.