Derek, have you tried Atlas TI? I have just started tinkering with it on the advice of a colleague who's used it pretty happily for analyzing conversations. I personally am working on blog comment threads with it. So far it's been a little frustrating -- there's some massaging of text files needed to get the comment threads into the program, and then tagging is a little difficult -- but I think it's more because I am not well-practiced with the software yet. All in all it seems to have a hugely rich ability to create tags and themes, and to display these in a variety of ways. The big benefit of Atlas TI is that once you've run out your 30-day trial period, a grad student license for the software is only something like $100. Not sure what it runs for professors, but for me, this is a pretty big help. I'd be interested to hear from anyone else who's used Atlas TI as well. Gus