Learning from video vignettes is a theoretically grounded and popular professional development activity. In online professional development communities, however, responses to video are often shallow and lack meaningful commentary about the issues that surround teaching and learning mathematics. Given the lack of apparent involvement with the video content in online commentaries, this investigation examined whether more deeply analytical comments could be elicited from pre-service teachers in response to video clips posted to the Everyday Mathematics Virtual Learning Community (VLC). By altering the framing conditions that accompany video clips on the VLC, this experiment tested whether differences in prompts caused variations in pre-service teachers' depth of commentary. Findings highlight the malleability of pre-service teachers' commentary, as responses were more analytical when asked to focus on the teacher portrayed in the video; when asked to focus on students' understanding, contrary to expectations, pre-service teachers' responses tended to be descriptive. Yet these descriptions were not simple, but rich and detailed. This may be a fundamental precursor to analysis of student thinking—and perhaps an appropriate first step for novice or pre-service teachers
