There is a 2-layer sign-in process, first you need an O'Reilly account, then you have to register for the webcast.
It's essentially a 1.5 hour long info-mercial for both Beagleboard.org and "Beaglebone Cookbook" with the two authors of the book discussing numerous Beagleboard topics.
It's really good. What I got out of it is a better understanding of the history and motivation for Beagleboard.org.
It's really starting to branch out and you will see where they are headed with this technology.
Starting about 80 minutes in there is a discussion of the Device Tree and how it relates to "mainline Linux". Worth a listen!
I watched using Firefox in Ubuntu 14.04. O'Reilly's media player is one of the best I have seen. There is a row of icons at the bottom you can use to control the session.
Very informative presentation by authors Mark Yoder and Jason Kridner!