Japanese social app to take on Facebook in US Line, which already has 230 million monthly users, lets users exchange text messages, graphical 'stickers' and video and audio media, as well as make free VoIP calls, and hold free audio or video conferences. Originally developed as a mobile application for Android and iOS smartphones, the service has since expanded to BlackBerry, Nokia Asha, and Windows Phone, and also exists in versions for laptop and desktop computers. Stickers - which are used during chat sessions between users and act as large-sized emojis - are one of Line's most popular features. Stickers feature original characters as well as a number of popular manga, anime and gaming characters, movie tie-ins, and characters from Disney properties such as Pixar. Users can purchase stickers as gifts, but many stickers are available as free downloads, depending on country availability. Purchased stickers are attached to an account and can be used on other social media platforms. Line says its users send more than 1 billion stickers per day. However, the company makes most of its money from games, with offerings like Line Pop and Line Bubble recently moving into the Top 10 lists on Google Play and the Apple App Store. Like other popular online game providers in Asia, Line lets users download its games free, making money through in-app purchases, which provide players with special powers, for example. As part of its plan to conquer the US, Line has teamed up with nine top video creators on Vine - the mobile app owned by Twitter that enables users to create and post short video clips - for a series of promotional videos. All of the creators are involved with Collab, the LA studio working with Line to run the promotion. "LINE is one of the most fun and addicting new mobile apps, so Collab is excited to help introduce Line to the United States market," said Collab chief executive Tyler McFadden. There's a lot of crossover between the young audiences on Vine and Line and we're confident that the Vine Influencers we work with will be extremely effective in driving new Line users.