In today's world of Github, Bitbucket, AWS/EC2, and Virtualization in General, it is helpful to understand public key authentication and SSH in general. The good news is that this seemingly cryptic and magical technology is quite easy to get a handle on once you know a few snazzy recipes.
BONUS: There are two easter eggs "hidden" plainly in the slides. Both are language constructs (one ruby-ism and one regex-ism). Where are they and what do they do?