The best takeaway message for me was the importance of having applications that cater to the specific needs of a law firm. Peter explains how it's great to use VoIP to replicate what they had before - law firms are not early adopters, and are not looking for the multimedia richness of IP - at least now. However, what he's looking forward to are third party apps that can help him address specific problems, such as billing - something lawyers are quite fond of. In the TDM world, this simply wasn't possible or practical, but with IP it's easy, and Peter looks forward to being able to pick and choose apps from various developers that suit him just right.
Peter certainly echoes the importance of apps being the real drivers of value, and the same story will hold for countless other vertical markets. So, for all the developers out there, this podcast should be a good listen.