No one could confuse Facebook with a company focused on privacy. In fact, over the past few years, the company has become the poster child for big tech violating the privacy of its users. Since the Cambridge Analytica controversy, the company has been forced to take a step back and reevaluate the way they do business. This has involved heavily researching the way their websites, apps, and APIs are used by third parties.
The first big move they made was against a company that was using an Instagram feature which showed photos based on location to track people's movements. When they found out what was happening, Instagram shut off access to the data. This was just the beginning, as the company has announced it has suspended tens of thousands of apps on the Facebook platform over privacy concerns.
All of this is part of Facebook's App Developer Investigation, which is a direct response to Cambridge Analytica. The program has analyzed millions of apps and "of those, tens of thousands have been suspended for a variety of reasons while we continue to investigate." It is important to note that the suspended apps do not mean that they are gone for god, or that the apps actually violated any privacy rules. Instead, the suspensions are temporary because the apps were suspicious and require further investigation. After that investigation completes, a permanent decision will be made.
While the majority of the connected apps have been suspended, some have gone farther, based on data acquired during the search. The company has banned a collection of high-profile apps, including one from a South Korean data collection firm similar to Cambridge Analytica. They have also filed suit against "two Ukranian men" for survey scraping, again similar to Cambridge Analytica.
The apps currently under investigation are ones that, like the apps that led to Cambridge Analytica, exist within the confines of the Facebook platform. Those include apps like Facebook games, survey apps, etc. External apps, like those which allow you to log in via Facebook, are not currently under the company's magnifying glass. That is because most of these apps ask for access to basic data, like name and email address. However, there is a realistic chance that they will be the next round of investigation.