This video comes from the O'Reilly Media conference Velocity and is officially entitled "A Day in the Life of Facebook Operations," presented by Facebook Systems Engineer Tom Cook. It's a pretty interesting look at managing the ever-changing systems environment at a company that has grown exponentially in six years.
Cook begins by going over some of the numbers Facebook is dealing with on a daily and weekly basis: over 6 billion pieces of content are being shared on the site every week, over 3 billion photos are being uploaded weekly and over 1 million Websites have implemented Facebook Connect's sharing services on their sites.
There are also details about the evolution of programming at the social networking company, and details on QA and how the sheer size of Facebook allows engineers to see very quickly how well or poorly their code will perform.
This video runs about 40 minutes.