Alibaba and Tencent are archrivals in China's burgeoning tech sector. Having carved up the consumer internet sector -- including social media, e-commerce, streaming media and mobile payments -- the two tech juggernauts are increasingly expanding beyond their core operations. And in every vertical they enter they wind up in fierce competition, creating a dichotomy in the Chinese market that sometimes forces domestic and foreign firms to choose between them when launching a new product or service. The rise of the two companies has been a blessing and a curse for China. While the investment and innovation they offer have helped the economy, the sway Alibaba and Tencent now hold over China's people and economy is putting the government ill at ease. But as much as it can't afford to cede authority to these companies, it can neither afford to rein them in too tightly....