The biggest data octopuses in the App Store

heyData Analyzed over 100 popular apps from the German Apple App Store

Since the launch of the iPhone in 2007, we have witnessed the rapid spread of smartphones firsthand. Since 2009, the number of smartphone owners has increased tenfold from6.3 million to62.6 million in 2021 (Statista). For almost all of us, mobile applications - apps - have become an essential part of daily life. On average, we spend almost four hours a day with and on devices(FAZ). From banking to transportation to grocery shopping and mental health care, there are now apps for almost everything. More than two million apps can be downloaded from Apple's App Store alone. More than 90 percent are free. This raises the question of how the developers of these apps earn their money.

A recent investigation of the Google Play Store has already revealed that some of the most popular free apps require for their use the require access to more than 70 private data points in some cases. Thanks to the GDPR, prior consent is required from the user, but once access is granted, apps can use our personal data to their advantage. For example, by selling it to other advertisers.

In our latest analysis, we took a look at Apple's App Store and examined more than 120 of the most popular iPhone apps in Germany. We wanted to find out which apps are particularly interested in our data to:

• Sell to third parties and advertisers
• to use for their own marketing
• use it to track us on other apps and websites

These apps diligently sell user data to third parties

The meta-apps Messenger, Facebook, and Instagram particularly monetize a lot of our "donated" data. Of a total of 32 access requests made by each of the three apps before use, a majority of 75 percent are used for third-party advertising purposes. Close behind is another U.S. platform giant, LinkedIn, followed by the Frankfurter Allgemeine Zeitung news app. 79 percent of the FAZ app's access requests are used to sell data to third parties for advertising purposes.

These apps always know where we are

Asking to access our location is not automatically negative. For transportation and delivery apps, such as Uber or Lieferando, the request is essential to fulfill the service. For other apps, knowledge of exact location seems irrelevant to the function. This raises questions. Some apps even use tracking to monitor our activity across the app on other apps and websites. Duolingo tops the list: The language-learning app makes 19 access requests, 68 percent of which are for tracking, some of which goes beyond the app.

These apps use data for their own advertising purposes

Companies also generate revenue from apps that are free to use by using them as a venue for their own marketing activities. In this area, too, the meta apps Messenger, Facebook and Instagram top the list. 75 percent of their access requests are for tracking for internal advertising purposes. Mobility platform Circ uses nearly 92 percent of its access requests for its own marketing. Among the dating apps, LOVOO is the app that most often uses our personal data for its own advertising.

The most date-hungry dating apps

Overall, LOVOO is the most data-hungry dating app with 25 private data points that are either used for tracking, third-party advertising, or internal marketing purposes. At the other end of the spectrum are eDarling, LoveScout24 and also Tinder, which are less data hungry. This makes them well suited for those looking for love without selling their privacy.

Monetizing health: the data octopus among mental health apps

According to the WHO, depression was diagnosed about 25 percent more often in the first year of the pandemic. This has led to a number of new apps that aim to help people improve their mental health. One uncomfortable fact is that some mental health apps, like MindDoc, indicate in the app store that they may sell our personal data to third-party advertisers. On a positive note, no other mental health app in our list does the same. Health data is some of the most sensitive data people can share.

The biggest data octopuses among messenger services

Messenger services and chats are among the most widely used smartphone apps in the world. Since their introduction, the importance of data privacy in these apps has been a hot topic. Some services have even made it their mission to offer the highest level of data protection and have become known for it. This includes the app Signal, for example, which does not request any personal data. In contrast, other services, such as Meta's Messenger and Snapchat, still use private data for tracking and advertising purposes.

Social media: Share photos and add private data

Social networks like Facebook and Instagram are extremely successful at monetizing our personal data. Because they collect so much information about us (54 personal data points in total each), these platforms have become gigantic marketing machines. The far-reaching user details that operators of these social networks capture and cleverly market generate billions of dollars in revenue. In contrast, Discord, Reddit, and Quora consider themselves social networks. The apps from these providers encroach far less on privacy when it comes to tracking or selling personal data.

The full list with results for all analyzed 126 apps from the Apple App Store can be found here. 

This is how the analysis was performed

Initially, 126 popular and free apps for the iOS operating system were researched (as of June 2022). In the course of a major privacy offensive by Apple, every app developer or provider is required to provide information about the following privacy notices: 

• Number of permission requests made to access our personal information (for example, to access our purchase or search history) 
• Information about which data is used for tracking purposes
• Information about which data is used for advertising purposes by third parties 
• Information about which data is used for advertising or marketing by the app developer itself

For all selected apps, all of the above points were analyzed. Finally, the apps were ranked according to the extent to which our personal data is used for tracking, third-party advertising, and marketing or promotion by the developer (from highest to lowest).