Lil Jon, the Atlanta rapper and producer who fronted Lil Jon and the East Side Boyz, built his early 2000s crunk hits around shouted ad-libs, with Yeah, What and OK becoming his trademarks. The OK shout was heard across club tracks and features, including the era that produced Usher's Yeah, and later crossed into television comedy and internet soundboards. Cut down to a standalone clip, it survived the crunk era as a meme reaction, reused whenever a creator needs instant, exaggerated approval without any extra explanation needed.