Fitness trackers provides tons of information, but probably the most valuable part of that information is that it's real time. It can tell google information a

Fitness trackers provides tons of information, but probably the most valuable part of that information is that it's real time. It can tell google information about your routine even when you don't have your phone on you (wake up and leave your phone on the nightstand while you get around? Now Google knows you're not asleep.) I haven't had a Fitbit in years, so I'm sure some have GPS, which would increase the footprint of GPS tracking for runners that don't run with their phone (even if that not many), then you're getting ads about healthy food options near the start/stop point of your trail. It could tell Google if you've been having trouble sleeping, then you're getting sleep aid or sleep study or high end mattress ads. I'm sure the fitbit can detect certain workout routines based on physical movement, and can cater ads to users based on whether they're weight trainers or endurance trainers as well as skill level. I think there is a ton of high value information that can be gathered from a Fitbit for Google.