Facebook wasn't able to get a similar app approved due to changes in Apple's rules, and so it used the aforementioned enterprise certificate program, run by Apple, that is only for internal-use apps to get around the restrictions, an investigation by TechCrunch this week revealed.
Facebook has secretly been paying people between the ages of 13 to 35 money to install an app called Facebook Research. This has been going on since 2016.
Facebook said all of its employee-only iPhone apps are offline and that it's working with Apple to negotiate the issue.
Last year, Apple removed Facebook's Onavo security app from the App Store because it did not comply with its privacy rules that stated apps "should not collect information about which other apps are installed on a user's device".
The TechCrunch pieces argues that Google is more straightforward here, compared to Facebook, in explaining how the program works and what data is collected, while also pointing out that it's still somewhat dicey for this to exist at all.
The question now is, will Apple cut off Google's access to its developer system the same way it did with Facebook?
"Key facts about this market research program are being ignored", a Facebook spokesman said in a statement.
A Facebook spokesperson told Business Insider that it has no plans to end Facebook Research as a result of the report. It said that less than 5% of those who participated in the research were teens who signed parental consent forms. And Apple's move Wednesday restricts Facebook's ability to test those apps - including core apps such as Facebook and Instagram - before they are released through the app store.
"Any developer using their enterprise certificates to distribute apps to consumers will have their certificates revoked, which is what we did in this case to protect our users and their data", the tech giant added.
The Facebook Research app is side-loaded to the users' devices through Apple's enterprise certificate program and Apple's Terms of Service require that developers use it only for distributing internal corporate apps to their own employees.
But Strafach, who dismantled the Facebook Research app on TechCrunch's behalf, told the AP that it was mostly Onavo repackaged and rebranded, as the two apps shared about 98 percent of their code.
Strafach, who is CEO of Guardian Mobile Firewall, said he was aghast to discover Facebook caught red-handed violating Apple's trust. But BuzzFeed News reporter Ryan Mac tried signing up after the TechCrunch report was published, and found very few disclosures to participants that Facebook was behind it.
Google says it uses the anonymized. aggregated data to "understand how people watch TV across devices; make improvements to Google products like YouTube, Assistant, Android, and Google Play; create better ad experiences, which help us keep Google services free for everyone;" and "conduct analytics and measurement to understand how our services are used".