Mark Bernstein of Eastgate Software is the creator of the app, and I've been following his blog for some time (My two-sentence review: Thoughtful, well-reasoned, and "civilized". He sometimes uses words about food that I have to look up to understand. ). His book The Tinderbox Way is marvelous read, articulating many of the thoughts and inherent design tensions involved in architecting such a tool. I actually bought the book before I ever saw the software first-hand.
At any rate, the short version of this story is that I finally broke down and spent a couple hundred bucks for an old Mac G4 so I could check out Tinderbox personally.