Choose whether emails are sent as new messages to each recipient or as replies to your last conversation with each recipient. If you have no prior conversation with a recipient, the email will be sent as a new message. If you do have a prior conversation with the recipient, the email will be sent as a reply, and the Subject of your email campaign will be ignored, since the Subject of the last conversation will be used.
Email has been shown to generate a better ROI compared to other marketing channels. A survey by the Direct Marketing Association and Demand Metric of marketers in the United States showed that email achieved a median ROI of 122%, which was more than 4 times higher than other marketing channels, including social media (28%), direct mail (27%), and paid search (25%). And in 2016, email marketing generated $44 ROI for every $1 spent, which was up from $38 in 2015.