The answer said the Xbox One "does not have to be always connected, but Xbox One does require a connection to the Internet."
Developers are able to use Microsoft's Azure cloud computing service with Xbox One – this could potentially shift certain computations to the cloud and require players to be online, even for single-player runs, Wired reports.
For pre-owned games, the Xbox One is designed "to enable customers to trade in and resell games," Microsoft said in the same Q&A post, promising more details later.
All games can be installed to the Xbox One's 500GB hard drive, removing the need for a disc entirely after the initial load-up, Microsoft tells Wired. If a second account wants to play that game the player will be asked to pay a fee and install the game on his own console. Whether this is a mandatory installation for every game, Microsoft says, "On the new Xbox, all game discs are installed to the HDD to play."