Menlo Park (AP) - Facebook has employees listen to selected footage of users from his chat service Messenger and get typed.

Affected users who had turned on the transcription function for language entertainment, said the online network the financial service Bloomberg. The task of the employees was to check whether the software had correctly understood the spoken sentences. The news had been anonymized. The practice was discontinued more than a week ago.

In recent weeks, Amazon, Apple and Google had come under fire because they let recordings of language assistants software evaluated by employees, without it was known to the users.

For Facebook, the situation is even more explosive: For years the rumor goes around, apps of the online network listened to the users to personalize the advertising. Vouchers are cases in which ads match a previous conversation. Facebook always rejected the accusation, and founder and boss Mark Zuckerberg denied this in the spring specifically at a hearing in the US Congress and spoke of a "conspiracy theory".

Facebook had also stated that the online network processes audio data only if a user has granted permission. While it is clear that recordings have to be processed for a transcription function, users - unlike other tech companies - may not be aware that in some cases people have heard them.