Personalization for Marketing Automation is the technical aspect of identifying a user and attributing all their behaviors to them along a digital footprint. It's all the behind the scenes details that involves cookies and JavaScript snippets that work to gather information that can then begin to tell a story about the user. This helps an organization to deliver the right content, at the right time, with the right tone and feel. Since these cookies offer personalized experiences for the user - they fill out a submission form with all of our information for example - people tend to be okay when a website uses them. (Ask a millenial and they practically expect cookies to be operating behind every web domain!).  

Starting with the end in mind, you are going to need to sell Marketing Automation internally, so it's important to understand a high level view of what you are getting.