Some other points from the talk:
- Steam client is running nicely on Ubuntu and many developers have approached them with good game products.
- Cooperation with Canonical has been good.
- Ubuntu is preferred platform as it has a large user base and good community support with a strong company like Canonical behind it.
- Linux has everything they need: good OpenGL, pulseaudio, OpenAL and input support.
- New Source engine games will be available for Linux.
- No firm time frame for Steam Linux release, but soon.
- Copy protection is up to the game publishers.