MSN Messenger, Microsoft's instant messaging service that dominated online chatting in the 2000s, used a set of short notification sounds for sign-ins, messages and nudges, and the contact online tone became one of its most recognised cues. As users moved to newer apps, the sound lived on in YouTube nostalgia videos, TikTok edits and meme soundboards, where a single ping instantly evokes the era of buddy lists and status messages. Its brevity and clarity keep it useful today as a quick, recognisable signal for someone arriving online.