Facebook has been clandestinely accumulating written transcriptions of its users' conversations, which the social media giant recorded through their phone microphones.
That's according to third-party contractors who spoke to Bloomberg about the practice.
The contractors said that they were paid to listen in on countless, occasional vulgar conversations among Facebook Messenger users, though the company never explained to them why it needed the transcriptions.
Facebook later told Bloomberg that the human transcriptions were being used to test the performance of its speech-recognizing artificial intelligence - a troubling admission that the company regularly violates people's privacy.
Facebook told Bloomberg that it stopped the secretive project last week.
But in numerous hearings in front of Congress, CEO Mark Zuckerberg insisted that Facebook only accessed people's microphones when explicitly given permission to do so for features like voice messaging.
Zuckerberg never disclosed that Facebook was sending recordings to third party contractors.
It's that difference between Facebook's disclosures - Bloomberg reports that Facebook doesn't mention audio recordings in its data-use policy - and the tasks they were asked to do that spurred the contractors to come forward over concerns that their work was unethical.