Youku (NYSE: YOKU) and Tudou (NASDAQ: TUDO), two of the leading China-born the U.S. listed online video site announced today that the two have reached a definitive agreement for Tudou to combine with Youku in a 100% stock-for-stock transaction. It seems that the news took many people by surprise, Weibo users’ reactions were like “seriously? seriously?” or “Youku and Tudou? It was a tough year last year for Chinese online video sites as costs of copyrighted content are ever rising. Youku and Tudou were constantly fighting with each other over copyright issue, both accusing each other of using each other’s exclusive content.