Whenever you send bulk email, it's likely that some of your contacts will unsubscribe. This isn't always always a bad thing; sending to recipients who are not opening your emails can affect your overall sending reputation. It's better that these people unsubscribe properly, rather than report you for spamming.
If a contact clicks the unsubscribe link in your email, they will be asked a very quick (and optional) one question survey asking them why they are unsubscribing. The Email Unsubscribe Report tracks the data collected from this survey.
This is a ranked list of the reasons that people gave for unsubscribing via this email. In addition to the totals and percentages, it also shows you in-line charts of the previous 10 emails allowing you to track the trend of each reason.
The reasons offered for unsubscribing are: