The present study concerns itself with a socio-cultural study of the relationship among language, culture, and society. The underlying philosophy for this study can be put like this: Language is a social mirror reflecting a constellation of insightful things that deserves a scientific analysis. Bearing this principle in mind, it is argued that a sociolinguistic study of language use in daily life will capture something that otherwise will be ignored in linguistic study. There are four parts in this paper. After a brief introduction to the research background, we introduce three major traditions in the study of language use from a scoio-cultural perspective. They are the London School, the North American School, etc. Part Three emphasizes the importance of a socio-cultural study of language use by summarizing some interesting patterns in virtual communication and by examining some typical cases in cross-cultural misinterpretation. The significance of sociolinguistics is further stressed in the closing part.