The purchase is Baidu's latest step to diversify beyond its core search sector.

The string of M&A deals has highlighted the heated competition among Internet giants to secure dominance of the mobile Internet market as an increasing number of Chinese are going online through mobile devices.

Currently, Tencent, which has so far attracted 300 million users to its popular voice messaging platform Wechat, is widely regarded as having secured a dominant seat in the mobile Internet market.

But Ma Huateng, Tencent's chairman and CEO, took a cautious view about the company's position.

"No matter how well-placed we are now in the mobile market, a slight oversight may cause a shipwreck," he said at an Internet conference earlier this month.

According to data from the China Internet Networks Information Center, China had 420 million mobile Internet users as of the end of 2012.

With the market potential yet to be tapped, the Internet giants' M&A activity will likely to go on for a while, according to Li.