Gamers such as Kolodi say they like sports but fail to click with traditional ones such as football or baseball. Some are casual gamers. Others are looking to boost their skills or go pro. They are coming out of their parents' basements and online gaming communities, buying tickets to watch tournaments. About 10 million unique visitors watched the big-league Overwatch games in the first week, the league said. The online streamer Twitch has reportedly agreed to pay $90 million to stream the games for the first two years. Sponsors such as Intel, HP, Toyota, T-Mobile, and Sour Patch Kids are shelling out big bucks for advertising. Some say the market could reach $5 billion by 2020.