This is how the new in-game friend score comparison feature works! This is taken straight from the forum.
This is the Delivery skill game. You have to haul the cart filled with bombs as far as you can in one minute time limit. If the bombs are shaken too much or fall out of the cart, they will explode. The score is simply the distance how far you can reach before the bombs explode or the time ends. While riding the track you can see the gamertags (player names) of the top 10 players in your friend list showing the positions where they have reached.
This is one of the new hard racing tracks, called King of the Hill. You can see the friend comparison meter in the top of the screen. It shows in real time how much ahead/behind you are compared to the friend that is closest to you currently (and the player ranking – a feature not yet shown in this old screenshot). If you ride much faster or slower compared to the friend shown, the comparison meter will automatically swap to another friend that is closest to you. So you have always someone to race against. Currently I am racing against “jorsai2″ (one of Jorma’s test profiles).