This document takes a look at different uses and the pedagogic implications of using discussion boards in your module. Whilst it is not a technical document, it does focus on the pros and cons of the discussion boards provided in Blackboard. However, there might be something of interest to anyone using on-line discussion boards.
http://docs.google.com/gview?url=https://blogs.tees.ac.uk/lteonline/files/2015/02/PedagogyGuideDiscussionBoards.pdf&embedded=truePedagogyGuideDiscussionBoards
Good Practice Guide to Discussion Boards