The world has Google. China has Baidu.
Baidu is the primary and probably only search engine that hundreds of millions Chinese use everyday.
Baidu is similar to Google in most ways. It was created by Robin Li, a Chinese who got doctoral degree worked in USA before he created the company in 1999, one year after Google was established. Baidu went public in NASDAQ in 2005. Even Baidu's homepage is a Google-like concise page with a search box occupying the center of the page.
However, Baidu and Google are fundamentally different. The difference can be no more obvious when you put exactly same words in the search box of these two. The results from the two will be different. That's no surprise. What's astonishing is how different they are. For example, if you type in "tiananmen square", Baidu will give you the description of this famous sightseeing in China but nothing remotely related to what happened in June of 1989, while Google will give you among the top 10 results the "Tank Man" picture that shocked the world at that time.
Many other examples like this make you suspect whether there is a parallel world that we have never seen. Things viewed as common sense in one world was unheard by people in the other world. The first world is the world of Google, the other is the world of Baidu.
Chinese people who live in mainland China rely on Baidu as the main source of information, not because Baidu is more technology-advance but becasue Google is prohibited in China.
This difference separates China from the rest of the world.