acceptable spam report rate

An acceptable spam report rate is a metric set for how many of a company's marketing or status emails are reported as spam, also known as "junk mail," or unsolicited bulk messages sent through email. For most email carriers, the highest number of emails that can be marked as spam is 0.1%. Once a particular IP address reaches a high number of spam reports, the subsequent emails sent from that address might include a warning message that alerts users that the email is likely spam or they will automatically be placed in a junk folder. The IP address might also be blacklisted if enough customers report its messages as spam. 

Companies try to stay under the acceptable spam report rate by limiting the frequency of their correspondences, avoiding certain keywords associated with spam messages, including a link that allows the receiver to unsubscribe from emails and by using proper grammar, professional typography and graphic design. Marketing professionals also try to make sure that their content is honest and that the distribution list goes to people who are actually interested in the message.