Thanks to the popularity of online games like League of Legends, more people than ever are watching eSports -- and this trend is set to continue for many years to come. Around 2.4 billion hours of eSports videos were watched during 2013, according to a new report from IHS Technology. That's nearly double the 1.3 billion hours watched in 2012. And the analytics firm estimates that this total will be up to 6.6 billion hours by 2018, with China the largest market for online eSport views in the world, followed by the U.S. and South Korea. League of Legends was the most popular eSport in terms of hours viewed in 2013, followed by Dota 2 and Starcraft II. IHS senior director Dan Cryan says that streaming platform Twitch has been a large component in causing this great influx, with people watching live streams of eSports nearly tripling in 2013. Azubu and MLG are also boosting these figures, while YouTube, Dailymotion and Tencent continue to provide more generalist services for watching eSports. By 2018, IHS believes that the eSports video scene will be worth around $300 million per year in online global advertising revenue. "While advertising in and around games has often proved to be a difficult proposition, advertising in online video is commonplace,” said Piers Harding-Rolls, director at IHS. “This form of advertising gives games companies a much better opportunity of accessing the advertising value chain in a successful and meaningful way and offers these companies a route to profitable return on investment from their eSport initiatives."