Discord, a messaging service that's been called the Slack for gamers, makes it easier for people to talk to gamers across the world via voice or text. It's got quite the fan base too, with 130 million registered users worldwide. And with Discord synced to your Xbox, it'll be easier for you to see what your friends are playing whether or not you're on your Xbox.
Discord integration is part of Xbox's May update for the Xbox One line of consoles. The update also brings new features like higher 120Hz video refresh rate support for smoother graphics and the ability to more easily trim recorded game clips.