sourceMicrosoft has explained how Xbox Live Gold and digital game sharing features will work on Xbox One. To some degree, it's the revival of the nixed Family Sharing feature originally announced earlier this year. Here's how it breaks down.
Anyone can access your digital library via your Xbox One and use their Gamertag to play games. The license is tied to the hardware rather than the original purchaser alone. That said, you can also play and share games on other Xbox One consoles, and any purchases made on a friend's Xbox will be available on your primary console as well. Separate from the DVR functionality and Skype app, you will not need Xbox Live Gold to share your digital games locally.
On that note, Xbox Live Gold is also tied to your console rather than just your Gamertag. Regardless of whether or not the console owner is connected, friends and family can log in to their accounts and use Gold features, and you can do the same on their Xbox. Essentially, only one user needs a Gold account: Anyone using a Gold machine can access Gold features, even if they're not a paid subscriber.
Update: Microsoft has clarified to IGN that Xbox Live Gold is not required for digital game sharing; a subscription is only necessary to share access to entertainment apps and multiplayer gaming. As digital game sharing a local-only feature -- one user logging into a friend's console, for example -- games can be shared between users' Xbox One consoles without a subscription.
Seems like Goldless Xbox one owners won't have much to play with.