Blogs have permeated into our daily lives at a fast speed, and various kinds of blog spaces have attracted our attention. However, little effort has been made on studying the users’ motivation to participate in blog activities. This paper aims to construct a theoretical model about the blog adoption based on technology acceptance model (TAM theory), social capital theory and social exchange theory, and put forward 18 related hypotheses. Then the survey method is adopted to analyze the data from 208 questionnaires using the SPSS and LISREL tools, and to examine the theoretical model and hypotheses. Finally, the paper makes a discussion from five aspects due to the results of data analysis, including individual driving factors, group driving factors, community driving factors, technology acceptance factors and moderating variables. The results show that curiosity/enjoyment, user’s experience, social interaction and social identification will greatly affect users’ motivation to accept a blog; meanwhile, perceived ease of use, exchange cost and trust will partially influence users’ intention to participate in blog activities. The results also suggest that age and education degrees have significant moderating effects on users’ acceptance and updating of blogs.