Mark Zuckerberg, chief executive of social networking site Facebook on Monday toured the offices of China's top search engine Baidu, sparking off speculation that he is looking for opportunities in the world’s most populous country and the largest Internet market.

He expressed a business interest in China and has even studied Mandarin although the social network is blocked on China’s mainland.

Zuckerberg, who is accompanied by his girlfriend Priscilla Chan, on a visit and without any entourage, had lunch with Baidu CEO Robin Li. However, Kaiser Kuo, director of internal communications of Baidu said he didn’t know what they talked about though he did mention that the two had met before.

“Mark has had a long personal interest in China,'' Kuo was quoted as saying.

In October, Facebook founder had also hinted that he is more interested in more than that. “How can you connect the whole world if you leave out 1.6 billion people?''

However, Kuo tried to play down such speculation. ``C'mon people. Robin and Mark have known each other for a while. Mark's interest in China is well known. Keep the speculation in check,” he tweeted.
Zuckerberg is Time magazine’s 2010 Person of the Year although not many in China are familiar with Facebook, according to Kuo.

His schedule in China is not known. Zuckerberg paid a visit to a Tibetan temple on Monday morning.

Facebook, Twitter and YouTube among many sites are blocked by China following Internet censorship that is in place and as it deems Internet content politically sensitive.

Reports said China's nervousness about the power of social networking was on display on Monday, when the computer scientist seen as the father of China's ``Great Firewall'' of Internet controls apparently was forced offline by angry comments within a few hours of opening a microblog.

Anonymous posters peppered the microblog of Fang Binxing with hundreds of caustic or sarcastic comments, and eventually all of Fang's posts and the responses were taken down.