MSN Messenger, Microsoft's popular instant messaging service of the 2000s, used a short chime to tell users a new email had arrived in their linked Hotmail inbox. As Messenger became a daily habit for millions, the sound became shorthand for being online and waiting for a reply. After the service closed, the clip survived through nostalgia videos, reaction edits, and soundboard uploads, where it now works as an instantly recognisable cue for old internet culture and incoming messages.