What do the various states under Launch Date for a sent email indicate?

For sent email the Launch Date column indicates the date and time your email was launched. During launch however there are various states indicating where in the launch process your email campaign resides. Following are a list of the status messages you may see.
 
Pending Approval - Once an email is launched it is reviewed to ensure compliance with VerticalResponse policies and CAN-SPAM legislation. Once reviewed and approved the email will move to a Pending Launch state until the designated launch time/date.
 
Pending Launch - This status designates the email has successfully cleared the screening process and is set for launch. The campaign will be mailed at the designated launch date/time.
 
Mailing in Progress - This status indicates your mail message is in the process of being delivered to your recipients. For a small list this takes minutes, larger mailings may take additional time to complete.