The whistle became familiar as the default notification tone on WhatsApp during the early smartphone era, when the app replaced SMS for many users worldwide. Its short melodic call stood out from generic phone beeps and quickly became shorthand online for receiving a message. Creators lifted the sound for edits, memes and pranks, and viewers learned to associate it instantly with a private chat arriving. It remains popular because almost every audience recognises it without explanation, making it useful even in videos that never show a phone screen.