Xbox One games will require a one-time activation code to use, but you'll still be able to trade and sell them online, Microsoft tells Kotaku—although we're not 100% clear on the details. Speaking to us at the big event in Redmond today, Microsoft corporate vice president Phil Harrison clarified a couple of details about the system's used game policy and explained that there will be a solution for people who want to trade games with their friends. Here's how the system works: when you buy an Xbox One game, you'll get a unique code that you enter when you install that game. You'll have to connect to the Internet in order to authorize that code, and the code can only be used once. Once you use it, that game will then be linked to your Xbox Live account. "It sits on your harddrive and you have permission to play that game as long as you’d like," Harrison said. Other users on the console will be able to play that game as well, Harrison said. So you don't need to buy multiple games per family. "With the built-in parental controls of the system it is shared amog the users of the device," he said. But what if you want to bring a game disc to a friend's house and play there? You'll have to pay a fee—and not just some sort of activation fee, but the actual price of that game—in order to use a game's code on a friend's account. Think of it like a new game, Harrison says. "The bits that are on that disc, you can give it to your friend and they can install it on an Xbox One," he said. "They would then have to purchase the right to play that game through Xbox Live." "They would be paying the same price we paid, or less?" we asked. "Let’s assume it’s a new game, so the answer is yes, it will be the same price," Harrison said. But that doesn't mean used games are dead. In fact, Harrison told us, you'll be able to sell your Xbox One games online. "We will have a solution—we’re not talking about it today—for you to be able to trade your previously-played games online," Harrison said. The Xbox exec wouldn't give further details on how this system will work, but we're assuming that once you're done with a game, you can trade the code online and it will be erased from your machine. But what will you get? Other games? Microsoft Points? No matter how the final system works, it is not likely to please GameStop, the world's biggest buyer and seller of used video games, but it could be a tantalizing way to share games with your friends in the virtual space.