Facebook founder Mark Zuckerberg visited Sina's Beijing offices on Wednesday, as the billionaire executive continues his tour of China's biggest Internet companies.

Zuckerberg is said to have had an "information exchange on the Chinese Internet market" with Sina Chief Executive Officer Charles Chao during their meeting, and reportedly discussed Sina's microblog service.

Sina says that it may add advertising next year on its "Weibo" microblog site.

The company has also agreed to partner with Microsoft's Internet venture in China on Web services, including microblogging and instant messaging.

Sina currently ranks second here in China behind Baidu, China's biggest search- engine.

The meeting with Sina follows Zuckerberg's tour of Baidu's offices and China mobile earlier this week.