After announcing earlier this week that it had taken down hundreds of fake accounts due to “inauthentic behavior,” Facebook has now revealed it has suspended over 400 applications due to concerns about how user data was handled…

In a blog post, Facebook’s VP of product partnerships Ime Archibong explained that the most notable ban thus far has been of an app called myPersonality. This app was a popular personality quiz and was active primarily prior to 2012.

Facebook says, however, that the app failed to agree to an audit request and that “it’s clear they shared information with researchers as well as companies with only limited protections in place.”

As a result of these findings, Facebook says it will notify around 4 million people who chose to share their information with the myPersonality application that their data “may have been” misused:

Further, Facebook notes that at this point, it does not have evidence myPersonailty accessed any friends’ information – thus meaning it will not notify friends of those 4 million users.

Facebook explains that it continues to investigate applications that may have accessed user data. It says it has suspended “more than 400 due to concerns around the developers who built them or how the information people chose to share with the app may have been used.”

More information can be found in Facebook’s blog post right here.