This study focused on formative use of peer feedback in an online system that was used in basic computer literacy for word processing assignment-related purposes. Specifically, the effect of quantity, modality and satisfaction of peer feedback provided through the online system on students' performance, self-efficacy, and technology acceptance was investigated. Participants were 32 freshmen elementary and Turkish education pre-service teachers who were enrolled in two sections of the mandatory Computer I course in a public university in Turkey in the fall semester of 2013. Groups of students who submitted their assignments and received feedback in varying quantity and two different forms (text or text and video together) did not differ respectively in terms of students' performance test scores as well as self-efficacy and technology acceptance ratings. Students' feedback satisfaction ratings were significantly correlated only with their technology acceptance scores. All results were interpreted with the support of peer feedback content in both text and video formats to clarify the details and contribute more to the literature.