tarpitting

The practice of artificially delaying server responses for specific SMTP communication patterns that indicate high volumes of spam or other unwelcome e-mail messages. The intent is to slow down the communication process for such e-mail traffic so that the cost of sending spam increases for the person or organization who is sending the e-mail. [Exchange 2007]

The practice of artificially delaying server responses for specific SMTP communication patterns that indicate high volumes of spam or other unwelcome e-mail messages. The intent is to slow down the communication process for such e-mail traffic so that the cost of sending spam increases for the person or organization who is sending the e-mail.