Read Receipt

A read receipt is a notification that tells you your message has been opened or seen by the person you sent it to — often shown as "Seen" or a change in the message's status marker.

Read receipts add clarity (you know your message landed) but also social pressure (the other person knows you saw theirs). This is why some platforms let you turn them off.

In the context of chat etiquette, read receipts are what make "being left on read" — seeing a message but not replying — visible, which is a small but real source of social friction.