This paper discusses "Comments," a computer tool developed to study computer support for response to writing. The paper presents two primary theoretical perspectives to support the use of response to writing in learning to write: (1) writing is a social act; and (2) writing is a skill whose acquisition requires more than one reader so that writers must grapple with different readings. The "Comments" program, as implemented with five classes of highly motivated, high ability freshmen students for three semesters at Carnegie Mellon University (Pennsylvania), is described in terms of intended audience, contribution to student needs, use of computers as compared to pen and paper technology, and software features. The impact of the "Comments" program is discussed with respect to using statistics, skill acquisition, student attitudes, and patterns of interaction. Four figures representing the "Comments" program and 20 references are attached. (NH)