I finally got around to listening to this today, and I thought it was actually pretty dull. I think it doesn't help that Geoff is generally kinda dry, stuffy, and formal and Gabe is also kinda dry, stuffy, and formal. People have built such a cult of personality around Gabe Newell that I let myself forget that he's actually not this charismatic character, but just a thoughtful and plainspoken everyday nerd.
I thought that the Tone Control podcast was a better example of longform developer chats, though the production values on it were pretty low. I hope Keighley continues though, and can get some more lively chatters involved.
Gabe talked about how they don't want to waste their time on a technology like mobile/tablet/phone and how the always evaluate how long a platform/technology might be useful or relevant before they make a heavy commitment to it. Which is bizarre to me because at the end of the day the Steam box seems to me like a pretty massive waste of time, based around a rather paranoid assumption that Microsoft was going to lock them out of the Windows platform. I don't think Keighley should have really called him out on it, but I would like to have heard him justify why they should ignore mobile and maybe better explain why he thinks Steam Box is a platform with 10-20 years of viability.