Baidu founder and CEO Robin Li has been at pains to downplay a recent challenge to his company's iron-clad grip on the Chinese search market from Internet upstart Qihoo 360. But when you're going up against one of the scrappiest members of China's contentious Internet entrepreneur club, it's hard to keep your name out of the headlines.

Baidu BIDU -0.77% sued Qihoo in October, saying the antivirus company had made illicit use of Baidu content in the new search engine it launched in August. Qihoo founder Zhou Hongyi shot back, accusing Baidu of purposefully pushing negative articles about his company to the top of Baidu searches. The fight led to the two companies signing a fair-play code of conduct following intervention from a government-backed industry group