An interesting social feature of Xbox One's Achievements system has been unearthed. When playing local multiplayer it'll be possible to colour-code achievement pop-ups so that you'll know who gained the achievement.
Polygon reports that you can see the new feature at the 11:15 mark of this video:
The current system on Xbox 360 sees the Achievement-winning player identified by a flashing light on that corresponds to the their pad. For Xbox One, you'll be able to choose what colour you'd like to identify you and represent your tremendous gaming prowess.