After all the discussion about comparing email marketing with Search Engine Optimization and other marketing tactics, I still believe you cannot always compare. Search Engine Optimization concentrates more on Organic Traffic and Referral traffic, while email marketing is a direct marketing that enables you to hit the inbox of your target customer right away. But in that case, indeed you need to have a targeted list, otherwise no one will even open. And you will end at low open rate and even lower click through, high bounce and even spam complaints.
Therefore, first thing to consider in email marketing is undoubtedly a targeted, hygienic list of current email inboxes. Then you need to have a good email infrastructure configured with all required measures devised by email industry and major ISPs.
Regards,
adnan.ahmed227 @ Skype