As promised, Valve Software has published video recordings of all of the presentations given at the inaugral Steam Dev Days developer conference event, hosted in Seattle last month.
A new Steamworks Developer channel has been established on Youtube
for the purpose, with 28 talks spanning the multitude of game development and industry aspects that Valve has a stake in, from user-generation content and in-game economics, to SteamOS and virtual reality.
A full descriptive list of all of the presentations is outlined on the Steam Dev Days website
including links to the full PDF and Powerpoint slides accompanying the videos.