Daily Stat Comparisons
When you tag other friends you rode with on any given day, you'll be able to compare how you stacked up vs their stats in-app along side yours. You'll find these comparisons down towards the bottom of each activities' summary screen.
One important note: these stats / rankings are daily rankings. Sometimes people will record with Slopes in the AM, take a long lunch break, and then record again in the afternoon. The stat rankings you see on this screen take into account everyone's daily totals, as to not punish people that prefer multiple recordings.