autoresponder – a program that sends an automatic form response to incoming emails.
email marketing – the promotion of products or services via email.
email spam – unwanted, unsolicited email.
ezine – an electronic magazine, whether delivered via a Web site or an email newsletter.
HTML email – email that is formatted using Hypertext Markup Language, as opposed to plain text email.
lead magnet – a specific deliverable that is offered to prospects in return for contact information, typically to join an email list.
opt-in email – email that is explicitly requested by the recipient.
pass-along rate – the percentage of people who pass on a message or file.
permission marketing – marketing centered around obtaining customer consent to receive information from a company.
sig file – a short block of text at the end of a message identifying the sender and providing additional information about them.
viral marketing – marketing phenomenon that facilitates and encourages people to pass along a marketing message.
see also:
Email Marketing Services & Tools
Email Marketing Discounts category at MarketingDiscounts.io 
(services, training, etc.)