The censor beep comes from broadcast television and radio, where a steady 1,000 hertz tone was used to mask profanity and comply with language rules. As editing software and soundboards spread online, that same short bleep became a standard tool for YouTubers, streamers and meme makers. It is now used as much for comedy as for actual censorship, signalling a rude word even in clips where nothing was really said. Its half second length makes it easy to drop precisely over a single word without interrupting the surrounding dialogue or timing.