Sounds fancy, but it's just a data measuring mechanism that gives you info on customer app visits.
An example would be Mixpanel or Google Analytics which tells you stuff like how many people are going and staying on your site, how many people are making accounts, etc.
Lauren: Our user base is growing exponentially. Jack: WOAH HOW DO YOU KNOW THAT. Lauren: This fancy graph in the analytics shows us, my friend. Jack: Math is power! Lauren: Uh...yeah. I guess.