In Microsoft’s own words, “Trade-in and resell your disc-based games: Today, some gamers choose to sell their old disc-based games back for cash and credit. We designed Xbox One so game publishers can enable you to trade in your games at participating retailers. Microsoft does not charge a platform fee to retailers, publishers, or consumers for enabling transfer of these games.”
There is one caveat though – game publishers have the right to prevent the reselling of their games if that is what they want, saying, “In our role as a game publisher, Microsoft Studios will enable you to give your games to friends or trade in your Xbox One games at participating retailers. Third-party publishers may opt in or out of supporting game resale and may set up business terms or transfer fees with retailers. Microsoft does not receive any compensation as part of this. In addition, third-party publishers can enable you to give games to friends. Loaning or renting games won’t be available at launch, but we are exploring the possibilities with our partners.” That’s a bummer now, isn’t it?