Lai Yun, vice-president of Milanoo.com, a Chengdu, Sichuan-based wedding dress retail website, said it spends 6 to 9 percent of its revenues on Google's services for overseas marketing.

The company, which does only export business, had a revenue of "hundreds of millions of yuan" last year.

"Google's revenues in China are mainly from its export business as it remains a quality channel for domestic advertisers to do overseas marketing," Analysys International said in a research note.

Google is also pushing its mobile business in China with services that enable advertisements to be shown on mobile applications, Web pages, mobile search results and online videos.

Advertisement requests through Google's mobile products increased by 120 percent from July 2011 to July 2012 in China, one of its top five countries by advertising request volume, John Liu, its corporate vice-president, said last year, adding that its mobile advertising activities are its fastest growing in the country.

In September and December, Google shut down its music and shopping search services in China, saying the two had failed to meet expectations.