From both a commercial and public relations stand point these forums just had to be. Now that Terragen is going mainstream as a commercial product with a four item product line, as part of a professional service to their high end user base; and the folks who will eventually use TG2 in production and VFX work would expect away to ask product support questions and receive answers to them in a timely manor.
With this in mind then and the fact that so many software companies are offering forum user feedback and some such as Nevercenter offering user cantered development of the software there had to be an official forum for the Terragen community.
The trouble with the Yahoo list was and maybe still is was the overriding feeling by some members of that list that they where not been listened to which lead to a lot of accusations and so forth been put around that at the end of the day could have been handled in a better way, but that is what can be said now with benefit of hindsight.
The problem with the Yahoo list that I can see is topic hijacking where people just copy and paste what the last poster said and 5 in every 10 posts that I have seen there has been like this. The other part of the problem that I see with the Yahoo list is topic drift, but form what I have been able to find out this is quite common with these kind of E-mail lists.
People are more sophisticated now with their exceptions about what they want form a software company and that company's product/s to be; deadlines are tighter and law suits are more common if you cannot deliver on time and under budget.
I think the nature of what Terragen will be will be greatly shaped to a greater or lesser degree to what is said in these forums and of course in the court of public opinion weather that's right, wrong or indifferent; in the end soup to nuts that's just the way things will be.
Regards to you.
Cyber-Angel