In case you don't know it:

Baidu (百度) (NASDAQ: BIDU) is a popular Chinese search engine. Its design resembles that of Google and features the capability to search news and images, among other functionalities. Baidu claims itself the biggest search engine in Chinese language. Its name translates to "hundreds of times" in English (Wikipedia, 2005).

A parody of Stephen Chow's comedy Flirting Scholar [ 唐伯虎点秋香 ]. Tang Yin [ aka Tang Bohu ] is a renowned poet and painter in Ming Dynasty. This commercial mimics a scene in the movie that Tang was forced in competition with another poet. The game ended up with Tang's victory and the poet's hematemesis. In this commerical Tang plays some tricks with a Chinese sentence by seperating the words in various ways to mean different things. His competitor, a foreigner who knows nothing more about Chinese but keeps claiming "I know" , is totally defeated by the trick because Tang "knows Chinese better."

This is the original sentence on the board:
我知道你不知道我知道你不知道我知道你不知道

I know you dunno I know you dunno I know you dunno. [ Sorry for my lame translation ]

Round 1: 我知道,你不知道,我知道,你不知道我知道,你不知道。
I know, you dunno. I know (that) you dunno (that) I know, you donno.

Round 2: 我知道你,不知道我,知道你不知道我,知道你不知道。*
I know you, dunno I (me). Know you dunno I (me), know you dunno. [ 我 in Chinese is both nominative and objective of I/me]

*I can't even get the sentence in Chinese. Any clues?

Round 3: 我,知道你不知道我知道,你不知道我知道你不知道。
I, know (that) you dunno (that) I know. You dunno (that) I know (that) you dunno.

Have you ever watched House of Flying Daggers?

Parody of the story of MengJiang. Her husband enlisted to build the Great Wall dies and gets buried under the foot of it. Mengjiang's tears floods and pushes down the Great Wall.