Due to its complex nature and inherent unobservable features, teacher change within a specific context has rarely been investigated despite its importance as an issue in teacher professional development. To meet this challenge, the present study explored how teacher change was nurtured with the support of a web-based writing platform featuring such functions as "teacher action logs," "student learning logs and writing records," and "discussion forums." The data included (a) the writing teachers' written commentary on students' texts, (b) the writing teachers' discussion transcripts, and (c) focus group interview transcripts. Results showed that teacher change in pedagogical beliefs was manifested through two cycles of written commentary that included preconceptions, evaluations, and re-conceptualisations of their commentary in terms of local and global feedback. The writing teachers' perceptions of the web-based writing platform were also addressed in this study.