Few studies have been conducted to see how blog-based peer response helps students to improve their writing revisions. The present study investigates peer comments made through blogs, the nature of the comments and their areas of focus, and the ratios of students incorporating suggestions made through blog-based comments into revisions of their writing. Thirty-two second-year English major students taking a 15-week academic writing course at Nong Lam University in Ho Chi Minh City were selected to participate in this study. The students posted their writings on blogs and, through blog comments, also provided and received suggestions for revision. The results indicated that though the comments on global areas were greater than those on local areas, the qualified comments (revision-oriented comments) were not guaranteed to be greater in the global area. The total revisions made during blog-based peer response were greater than the total revision-oriented comments delivered by peers. In addition, revisions at lower levels such as "word" or "phrase" needed less help from peers, whereas those at higher levels such as "sentence" or "paragraph" needed more help from peers. The study brings illumination for instructors who are considering whether to apply blogs to their writing classes.