Facebook listened to some users' conversations on its Messenger conversation app in order to improve its AI transcription services - a practice the company had previously denied. 

Following an investigation by Bloomberg, the company revealed that it employed third-party contractors to transcribe audio messages exchanged on Messenger aimed at improving AI transcription services for users who opted into the feature.

The company said that it was not randomly activating users' microphones to target ads, as some people suggested. Instead, it claimed it only used "totally de-identified audio snippets" and did not use the data for advertising purposes. 

A Facebook spokesperson noted that the practice was common among technology companies, including Amazon, Apple, Google, and Microsoft, all of which faced scrutiny for similar practices.

The incident raised questions about Facebook's honesty, integrity and lack of openness. It also underscored concerns about technology industry approaches to user privacy.