Chances are you did not go to Valve's exclusive Steam Dev Days event. The developer-only event didn't reveal much in terms of news, other than a redesign for the Steam Controller. However, it proved insightful and provocative for attendees.
If you want to learn more about the future of Steam Machines, and getting started with Linux development, you'll be glad to find out that all the talks delivered at the event are now available for streaming.
The official website has been updated with links to videos and slides for presentations. Some talks--like moving your games to OpenGL--will be rather technical, but don't you want any excuse to watch Gabe Newell talk about everything other than Half-Life 3?