As you know in your lead scoring settings you set up the values/ranking for relative score and relative urgency

 

Marketo has an algorithm running in the background that takes those scores and gives the lead a ranking or priority this is now called 'engagement" in Salesforce.

 

In this case the engagement number of  110 is  the new naming convention for "priority".

 

Screen Shot 2016-01-30 at 2.02.45 PM.png

 

To understand how Relative Score Value and Urgency Score are calculated refer to:

 

https://docs.marketo.com/display/public/DOCS/Priority%2C+Urgency%2C+Relative+Score%2C+and+Best+Bets

 

Credit to: Veronica Holmes who kindly explained this to me.