This article examines the structure of topic movement within face-to-face postgraduate university seminar discussion forums through a conversation analytic approach. The analysis of 12 audio recordings of seminars showed that in spite of clear differences in the management style of sessions by seminar leaders there were important consistencies in their normative structure of participation. Previous research has shown that the turn-taking procedures used as a basic organisational feature of the talk have been seen to result in a regular change of topic within seminars. Although the research here supports these findings, the data showed that topic change was only one aspect of the topic negotiation process. The analysis in this article illustrates that topic negotiation was an ever-present feature of the talk and that, in addition to frequent "successful" changes of topic, there were also innumerable "unsuccessful" topical interjections. One prominent source of such failure was the presence of overlap in the seminar talk. In addition to being of value to educationalists wishing to understand educational processes, this analysis is viewed as having significant relevance for the development of alternative distributed media for hosting interactive seminars as it shows the implications of the interactional "affordances" of learning environments for the achievement of interactive talk. This article suggests, therefore, that research and development in this field would benefit from detailed studies of the affordances of these alternative hosting media.