A study by French research organization Exodus Privacy and Yale University's Privacy Lab analyzed the mobile apps for the signatures of 25 known trackers and found that more than three in four Android apps contain at least one third-party "tracker." The Guardian reports: Among the apps found to be using some sort of tracking plugin were some of the most popular apps on the Google Play Store, including Tinder, Spotify, Uber and OKCupid. All four apps use a service owned by Google, called Crashlytics, that primarily tracks app crash reports, but can also provide the ability to "get insight into your users, what they're doing, and inject live social content to delight them." Other less widely-used trackers can go much further. One cited by Yale is FidZup, a French tracking provider with technology that can "detect the presence of mobile phones and therefore their owners" using ultrasonic tones. FidZup says it no-longer uses that technology, however, since tracking users through simple wifi networks works just as well.