Emails continue to be the most effective path towards a successful digital marketing campaign. While marketers are often fearful about the backlash in mass mailing, the ratio of complaints to lead conversions is actually pretty low as per advice from business consulting. Another observation recorded is the fact that while more than four-fifths of accounts are primary, it is secondary account holders who complain less. However, the latter also open their mails less and thus chances of them getting converted as final customer reduce greatly.