Alibaba has agreed to pay about $4.6 billion to buy the rest of video streaming service Youku Tudou. As Bloomberg Businessweek reports: “Ownership of Youku Tudou would help [Alibaba founder Jack] Ma deliver U.S. films and drama series to more than a third of China’s population as Alibaba battles Baidu Inc. and Tencent Holdings Ltd. for the attentions of Internet users.”