Constant Contact / Salesforce free integration

Hello, 

I found the instructional information on the CC / Salesforce free / included integration but there isn't any information on what it allows you to do between the two platforms. I am not referring to the paid integration from Cazoomi or other vendors, but the one that you can get right from the App Exchange (photo below):

Are there more details on what this integration allows or a video on how it works?