A recent Privacy International study found that 42.55% of the free apps in Google Play share data with Facebook, and many popular apps share data with Facebook the second they've opened.
According to the study, 61% of the apps the group tested automatically transferred data to Facebook the moment the user opened the app, regardless of whether or not that person has a Facebook account or if they are logged into that account on the device.
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Some of those apps sent detailed information to the social network that might be considered sensitive. For instance, Kayak sends Facebook information about people's flight searches, including their departure city, date, and airport as well as where they plan on, how long they like to stay, and how many people they are traveling with. It also shares information about the type of ticket someone is searching for.
Other popular apps that include the data sent to Facebook include MyFitnessPal, Duolingo, Skyscanner, TripAdvisor, Spotify, Yelp, Shazam, and Indeed.
Facebook has reportedly corrected the issue through a new version of its developer kit, but these apps have yet to implement it, or at least they are implementing it properly, Engadget reports.
The issue does not appear to affect iOS versions of the apps.
You can check out the full report for free here. It also created detailed reports for all of the apps that transmit data to Facebook immediately when the app is opened.
If you use any of them, it's worth knowing what information you're sharing when you do.