Sitecore and the powershell is a talk I've been looking forward to for a while. I'm a one man team so my life revolves around automation. The thought of being able to streamline my process and shave time off the labor intensive tasks that I engage in regularly, easily keeps my attention.
So the powershell is a windows utility that is built on top of the .NET library and provides a deep level of access to the system. The presenter is using, as an example, the task of installing a Sitecore instance through a powershell script. It's can be a common and time consuming task especially if you work in a company where rapid prototyping is needed for building proof-of-concept sites. I don't but still, it's good to know.
The presenter then takes it a step further by showing how you would apply the power of automated server setup to remote servers by making authenticated requests to multiple end points. He wraps up by going over a few pitfalls associated with scripting in powershell such as knowing to return powershell objects to the console so that you have a better context of information to pull from so that results aren't too vague.
The powershell can be accessed from within Sitecore Rocks giving you yet another reason to download and install it. To be able to dive in, you'll really need to catch up on powershell commands which you can read up on the secrets of powershell ebook. There's also a few other things you're really going to need to be familiar with as well to use this tool effectively such as working with serialized content, configuring client powershell access and writing custom powershell scripts. It's an incredibly powerful but it does assume you have a fairly comprehensive understanding of the technology you're working with.