This sound comes from Skype, the internet calling and messaging service that became especially popular on desktop computers in the late 2000s and early 2010s. Its message alert spread widely through everyday use in work chats, family calls, and gaming sessions. Even after Skype became less central to online communication, the notification remained recognizable. Creators still use it as shorthand for an incoming desktop message, and it often appears in nostalgic edits about older internet culture, webcam calls, and classic PC software.