Some mail servers limit emails one IP address can send during an amount of time. To cope with this, Email Marketer introduces a special delivery mode which can periodically slow down Email Marketer's fast email sending in order to allow slow Mail Servers to "catch their breath". This optional feature can help avoid overloading the slow mail servers and improve the sending success ratio dramatically. And Email Marketer is the ONLY bulk email software with this feature at the present time.