Baidu offers many services, including a Chinese language search engine for websites, audio files, and images. Baidu offers 57 search and community services including Baidu Baike, an online collaboratively-built encyclopedia, and a searchable keyword-based discussion forum.
Baidu was established in 2000 by co-founders, Robin Li and Eric Xu. Both of the co-founders are PRC nationals who studied and worked overseas before returning to China. In June 2011, Baidu ranked 5th overall in the Alexa Internet rankings. During Q4 of 2010, it is estimated that there were 4.02 billion search queries in China of which Baidu had a market share of 56.6%.China's internet-search revenue share in second quarter 2011 by Baidu is 76%。 In December 2007, Baidu became the first Chinese company to be included in the NASDAQ-100 index.