This widget shows the status of the emails sent and is broken down into several categories. 

Sending In Progress 
How many emails that are in the process of being sent but have not yet been received. Please note this statistic is independent on the time period. 

Email Sent 
These are emails that were sent and received in the Users inbox. 

Delivered 
The amount of emails that were successfully delivered in comparison to the previous periods. 

Opened 
The amount of email that were opened compared to previous periods. 

Clicked 
The amount of emails that were clicked on in comparison to previous periods 
 
Bounce 
The percentage of emails that were bounced while sending  

Spam 
The percentage of emails that ended up in the spam inbox  
 
Other 
Any other problem as to where an email could have been sent / blocked etc.