As on-line discussion becomes an increasingly important and significant aspect of teachers' professional education, most particularly as part of distance learning environments, there is a need to understand and develop effective analytic techniques that provide insights into the processes at work within these systems. The computer conferencing environment at the centre of this study is a complex, unstructured discussion forum, of a type increasingly found as a component of CPD courses. In these situations the evidence of knowledge building processes is a key concern which relates closely to aspects of design and methodology. Having carried out some initial explorations of analytic tools, and leaving aside for the moment the process of knowledge building and the techniques and methods of computer analysis (reported elsewhere) This paper is a further report of work in progress that considers project design, research techniques, ethical dimensions and other considerations that impact on the study of on-line learning.