The Newly Engaged section lets you view details about people who have recently engaged with you for the very first time. 

For example, if someone has been in your Salesforce database for a year, but engaged with you for the first time (by opening an email, visiting your website, attending a webinar, etc.) 30 days ago, then that person would appear in the Newly Engaged section (given that your time frame is set to include that date). 

This section breaks down the number of Newly Engaged people by Lead or Contact?, Role, Department, and Source. You'll notice that Source is a drop-down menu which can be easily changed to any field in your integrated database(s); simply search for or scroll to the appropriate field. 

The default time frame for Newly Engaged people is Last 3 Months, but it can be changed by clicking the timeframe drop-down in the top-right corner of the screen.

Pro Tip: Get sales users engaged by changing the time range to 7 days, and selecting your Ideal Customer Profile from the circle charts. The resulting data (in the table) should be very helpful for finding 'hot' leads and contacts!