This research attempted to categorize reflection in a Web-based portfolio assessment using the Chinese Word Segmenting System (CWSS). Another aim of this research was to explore reflective performance in which individual differences were further examined. Participants were 45 eight-grade students from a junior high school taking a computer course. The study results indicated that the words used most often in reflective journals fell into "cognition" and "evaluation" categories in comparison to "emotion" and "memory". Based on lexical attributes, reflection was thus classified into "cognition," "evaluation" and "mix". Cognition was the most common type, and "evaluation", the least; "emotion" and "memory" types failed to emerge. Although reflective journals tended to be short, the average scores on reflection were acceptably high, which implied it was the quality rather than the length of a reflective journal that students were primarily concerned about. In addition, significant group differences were detected in terms of word counts and reflection scores. The reviews of peer reflections were seldom fulfilled, and covered merely one-third of the peer work; there were significant group differences related to the number of reviews. The duration of peer reflection reviews was usually short, and again, significant differences were found across various duration groups. (Contains 1 figure and 7 tables.)