This paper reported on a study of using blogs as out-of-class assignments for the development of learners' writing competence. There were 36 students of English majors from an intact second language (L2) writing class participating in this study. A mixed method design was employed to obtain both quantitative and qualitative data. The results showed that blog-based peer feedback had a statistically significant positive correlation with learners' motivation, collaboration, and course satisfaction. The findings also revealed that the feedback was conducive to learners' self-reflection and self-confidence in L2 writing and could give rise to an enhanced L2 writing experience. The study concludes that group collaborative writing via blogging can not only encourage collaboration and self-reflection but also engage learners in noticing and co-construction of knowledge. Pedagogical implications and challenges are addressed and suggestions for future research are advanced.