Games for Microsoft's new Xbox One will be shipped as Blu-ray discs, but won't be required to be in the console disc-drive every time you want to game. Speaking to Wired, Microsoft confirmed that games will install to the 500GB hard drive one time and will run directly off the console.
You may be thinking that you could just hand over the disc to everyone you know. However, Microsoft tells the publication the games will be linked to a single owner's Xbox Live account. To add a second, you may have to pay a fee. As for used games, Microsoft didn't go into detail on whether you could just pop-up in a game and play without installing it to the harddrive.
Furthermore, Microsoft confirmed to The Verge that there will be no backwards compatibility of Xbox 360 games with the Xbox One - thanks to the difference of the core architecture between the consoles. However, Microsoft doesn't plan to kill-off the Xbox 360 from the start and it will continue to be sold for the time being.
Microsoft said there were no plans at the moment to make Xbox 360 downloadable to the Xbox One.