This article claims the way the Chinese eat Chinese food (sitting around a table with common dishes in the centre and everyone dipping their chopsticks in) engenders a sense of bonhomie or togetherness.

For many Chinese, suggesting separate servings to friends is tantamount to estrangement....soon after the SARS threat ended, the mention of infection was a no-no among friends...

Li Qiang, professor with the Sociology Department of Tsinghua University, says it is so because the Chinese attach great importance to a friendly, joyful atmosphere when dining together.

"In addition, Chinese traditional eating habits strengthen relationships between people,'' Li says, adding that if it were not for this purpose, many would not even think of going out and eating together.

Separate servings, on the other hand, are part of Western culture, which stresses individuality, the professor opines.

Li also claims

Common servings started from the Tang Dynasty (618-907 A.D.) when Chinese ate around a table and used their chopsticks to pick up food from the same dishes....

(link via rice cooker.)