- They mention Steam OS will improve performance and decrease latency for input, graphics and sound
- AAA game announcements for Steam OS/Linux soon
- for the time being, Windows/Mac streaming to Stream OS
- Music, Video, TV content soon
- Game sharing for family & friends

Bonus:

- new Valve job offering: Multimedia Software Engineers ( http://valvesoftware.com/jobs/job_postings.html ), mentions

Quote Originally Posted by Valve
Designs and implements unique worldwide interactive public relations events for Valve’s AAA game launch announcements.
HL3 confirmed? :P