It stands to reason that Xbox Live on Xbox One would adopt the basic features of social networking—following friends, activity feeds and such. Larry Hryb of Xbox Live explains how all of that works in this video of the console's Friends app.
Remember, your friends list expands to 1,000 under the new Xbox One, but you may also have unlimited followers, just like Twitter. Your feed on Xbox Live is filled up with features such as your latest game results and acheivements earned. So, think of it as a social network FILLED with bot-written updates on what everyone is doing in their games. Awesome, right?
OK, kidding. Let's give this thing a chance. Other features include favoriting people who are in your friends list, so you may more easily find them when you're looking to connect in a party or in a match. And yes, you still have full control over what you choose to share publicly, just like on Xbox Live with the Xbox 360. There's a more detailed explanation at the link if you missed something above.