https://www.theverge.com/2018/4/6/17206394/facebook-unsend-messages-feature-update-messenger-mark-zuckerberg

After TechCrunch reported that Facebook has been quietly deleting messages CEO Mark Zuckerberg has sent via Messenger, the company is now saying that the ability to retract messages will soon be available to all Messenger users. According to TechCrunch, an “unsend” feature is coming in the next few months, though it provided no further details on how this new function works. Messenger currently offers a Secret Conversation mode where users can set a timer on when messages will self-destruct, but all parties within that conversation are notified when their thread will expire.

Facebook has implemented an unsend feature in some capacities with its other products before. WhatsApp has offered an unsend feature since last year, which lets users revoke a message if they do so within a short period of time after sending. The message does not simply disappear, however; the note “this message was deleted” sits in place of the text, video, or photo. Instagram also has an unsend feature that simply makes the message go away as if nothing happened (unless, of course, the recipient has already seen the message or push notification). Users simply hold the message they want to delete and select “unsend” to clear it from history. The recipient in this case is not notified when messages have been revoked.