The phrase 21st century humor is not tied to a single video or creator, but is used across meme culture as shorthand for surreal, ironic comedy that thrived on short-form platforms. Clips labeled this way are shared as reaction sounds for edits that feel random on purpose, sitting alongside goofy ahh sounds and other absurdist meme audio. Its continued use comes from versatility: the 21-second length fits compilations, and the label instantly tells viewers to expect self-aware, chaotic jokes rather than a traditional punchline.