ICQ, launched in the mid-1990s as one of the first mainstream instant messaging services, let users keep a contact list and see when friends signed on, and its short incoming-contact chime became part of that daily routine. As later apps replaced it, the sound survived in clips, compilations and reaction videos as shorthand for early internet culture. Today creators reuse it to signal nostalgia, an old-school chat or a surprise online arrival, because even listeners who never used ICQ recognise its distinctive two-note pattern.