One of the nagging issues with the Xbox 360 is the fact that the friend list was limited to only 100 friends, even after the Xbox Live support for the original Xbox was dropped. Now it seems Xbox One, (not to be confused with the real Xbox 1) is expanding the list tenfold.
@MrJamesGeary We don't have any information on that specifically, but we are excited that we will be expanding the friends list to 1,000!^EM
— Xbox Support (@XboxSupport1) May 21, 2013
The Xbox Support Twitter revealed today (see above) that the Xbox One will now support up to 1,000 friends meaning that you can become friends with pretty much everyone you know and everyone they know and still have trouble filling it up unless you simply add everyone you ever have interacted with like it is Facebook.