Viber is a popular messaging and voice-calling app used around the world for free texts, calls and group chats, and its default SMS notification tone has become one of its most recognisable sounds. Because the chime is short, clean and instantly associated with an incoming message, creators on video platforms began reusing it outside the app as a shorthand for a text arriving. It remains popular today because almost everyone recognises the sound at once, making it a quick, believable way to add a phone moment to a short clip.