Anecdotal evidence suggests that instructor performance in the online discussion portion of online courses has a major impact on learning and learner satisfaction. If this is the case, faculty development is an important component of success. This paper describes the development of a taxonomy of six categories to describe instructor postings to asynchronous discussions in online courses. This taxonomy was used during the inspection of 18 post-graduate level course sections at a Midwest university. The resulting data show that there is considerable variation in faculty teaching styles, interaction, and the amount of content-related feedback. The process also allowed issues such timeliness of feedback and responsiveness of faculty to be quantified. In-depth interviews with instructors and learners with experience of online courses were conducted to validate the qualitative data.