Yesmail - Yesmail provides email marketing solutions that integrate mobile, web, and social channels for marketers.
PostageApp - PostageApp is an email management service that makes it easy to design, deliver, and manage all of the email that websites or applications send.
JangoMail - Description of the software: JangoMail software is a fantastic tracking solution system that many businesses can utilize for their marketing.
SendGrid - Learn why more developers choose SendGrid for their email deliverability service to send transactional emails triggered by web apps. Get started for free
Pobox - Pobox provides email forwarding, filtering, and mailboxes.
eWayDirect - eWayDirect is an Email service provider for brands looking for enterprise functionality.