More than 70 percent of smartphone apps are reporting personal data to third-party tracking companies like Google Analytics, the Facebook Graph API or Crashlytics. When people install a new Android or iOS app, it asks the user’s permission before accessing personal information. Generally speaking, this is positive. And some of the information these apps are collecting are necessary for them to work properly. But once an app has permission to collect that information, it can share your data with anyone the app’s developer wants to—letting third-party companies track where you are, how fast you’re moving and what you’re doing.
— source scientificamerican.com