Five months into the year, "Fortnite" is unquestionably the biggest story in gaming. The battle royale-style free play game continues to spread through word of mouth and a virality that has touched numerous aspects of society. And now it's driving hardware sales. Video game headset sales were up 78 percent year-over-year in the first quarter, with March alone seeing 9-percent sales growth, according to a recent report from research firm NPD Group.Source