He strongly maintains that there was no misuse of personal data:
"The reality is that all necessary consents were explicitly and repeatedly provided by all Facebook users when using the myPersonality app. Their data was fully anonymised before being used for academic research. Data was not sought nor obtained from users' friends. There was no misuse of personal data."
In fact, he claims that Facebook was very aware of what the app was doing. He recounts how Facebook certified the app back in 2009 and paid his travel expenses to a 2011 workshop because the social network wanted to encourage more academics to use Facebook data. What's more, Stillwell says he never refused an audit.
In its statement on the matter, Facebook says that the app "was mainly active prior to 2012." Stillwell goes a step further, saying that "the app has not been in use since July 2012, so this ban appears to be purely cosmetic." It's pretty disingenuous, he claims, for Facebook to now say that the company had no idea what myPersonality was up to. On the other hand, Facebook is investigating these apps at a greater depth and with much more scrutiny than it had previously.
It's interesting because it appears the researchers behind myPersonality had a positive and supportive relationship with Facebook up until the Cambridge Analytica scandal broke. This does raise the question of what exactly Facebook is looking at with its investigations, and whether the changes and bans are meaningful or just skin-deep.