This is the most up to date version of fast changing material. Even so, since the conference on June 12th the specification has changed. One of the problems with Grid that I mention in the talk is the lack of “gutter” columns and rows. This has now been added to the spec, and you can read more about it in this post.
I’d recommend taking a look at the other videos posted from CSS Day. It was an excellent conference for any interested in more advanced CSS subjects.