From the Marketo Email Use Policy:
"...You may not send any Unsolicited Email by use or means of the Marketo Service. "Unsolicited Email" is defined as email sent to persons other than: persons with whom you have an existing business relationship, OR (ii) persons who have consented to the receipt of such email, including publishing or providing their email address in a manner from which consent to receive email of the type transmitted may be reasonably implied."
The full text of the policy is here: http://www.marketo.com/trust/email-use-policy.php
An abuse report is a report that an individual sends to email@example.com alleging that a Marketo customer sent unsolicited email.
There are a number of reasons why someone might report abuse. Here are a few common reasons people report abuse to us:
- The person forgot they opted-in to the mailing
- The person received genuinely unsolicited email
- The person opted in, but the branding in the email was different than the branding on the opt in form so it was not clear the email they received was connected to their opt-in experience
- Someone signed up for your list with the wrong address, and the person who actually received your email felt it was abusive
For additional reference - Abuse Report Deep Dive