The sound comes from Facebook's mobile app, where a short alert has long signalled new messages, comments and other activity for users around the world. As the platform grew, that familiar pop became part of everyday phone life, and creators began lifting it for short videos, memes and reaction clips. It works because almost everyone recognises it without any explanation, so a single play can stand in for an entire notification. That shared familiarity is why it remains a popular choice for social media edits and comedy sketches.