I am a former user of Silverpop and would like to see the feature – Send Time Optimization available in Marketo. This functionality is an option other than scheduling an email for a specific day of the week, time of day – the system utilizes email activity logs to instead send the email when historically the recipient is opening his/her emails. This functionality greatly increased our open rates. Introduction of this functionality would be a work-around to accommodate time zone restrictions and allow for global customer engagement – nurture campaigns.