Task: Explanation
Input (English): "U mad" or "you mad" is an internet catchphrase commonly associated with trolling. The phrase is used both as a statement and a question. It was popularized after an incident on "The O'Reilly Factor" involving rapper Cam'ron and record producer Damon Dash in 2003. Host Bill O'Reilly was debating the effect of rap music on children. When O'Reilly began to interrupt Dash, Cam'ron stated, "Why don’t you want to let him talk? You mad. You mad." In 2004, the phrase was added to Urban Dictionary, citing Cam'ron as the coiner. Question:  U mad was added to what crowdsourced online dictionary of slang words and phrases In 2004 Answer: Urban Dictionary
Output (English):  In 2004, the phrase was added to Urban Dictionary, citing Camron as the coiner.