Email Glossary

A soft bounce is defined as a temporary problem, such as not being able to connect to the intended recipient’s mail server. A soft bounce is also recorded when the recipient’s mailbox is full or a connection is refused or dropped, which can occur when the recipient’s mail server is busy. Soft bounces may be retried at a later time.
Bounce – Block
A block bounce is recorded when the error code includes any language that refers to a blacklist or delivery issue. Blocked bounces can be generated from the sending IP, domain name, or message content.
Bounce – Hard
A hard bounce occurs when the recipient’s mail server replies with 5xx error, which in most cases means that the attempt to deliver to that recipient will never succeed. An example of a hard bounce error is does not exist, which commonly occurs when a list of members has not been contacted recently.
Bounce – Soft
A soft bounce occurs when the recipient’s mail server replies with an error other than 5xx, or never replies at all. An example of a soft bounce error could be caused by a server that overloaded or a user whose mailbox is full.
The original name of the authentication standard developed by Microsoft that later became SenderID
Passed in December 2003, the CAN-SPAM Act sets basic guidelines for sending commercial email messages in the United States.
Clickthrough Rate
The % of users that click on a message. This can be calculated using number of recipients that were scheduled, received the message, or opened the message.
Confirmed Optin
Conversion Rate
This normally refers to the number of recipients that take the final action, such as completing a form or purchasing a product or service.
This term describes the overall amount of messages that reached the inbox and can be attributed to a specific campaign or for a sender overall.
Delivery Rate
The % of messages delivered (not bounced) versus the total number scheduled.
Delivery Service Provider (DSP)
A third party that provides tools for monitoring the Deliverability and performance of email campaigns. This typically includes seeding the list to measure Delivery Rates at major ISPs, scanning the content for spammy words and broken HTML and rendering the content in various MUAs. Examples include DeliveryMonitor, Pivotal Veracity, and ReturnPath.
Domain Keys
The most comprehensive authentication standard that signs each outgoing message with an encrypted key. While SPF and SenderID involve making changing to DNS records, DomainKeys requires senders to change the way that messages are constructed.

Domain Keys Identified Mail (DKIM)

See Confirmed Optin
Email Deliverability
See Deliverability
Email Service Provider (ESP)
A service that manages a company’s customer database or list and provides tools for sending out different types of emails on a one-off or automated fashion. Most commonly used for “batch and blast” newsletters and email marketing, ESPs also provide services for managing transactional email messages, autoresponders, password reminders, alerts and more.
Open Rate
The % of users that open an HTML message versus the number of messages scheduled or delivered depending on the criteria. An open is captured when a user downloads a small, normally invisible image.
Multipurpose Internet Mail Extensions – A standard for sending non text information. Commonly an email message is encoded in a MIME format allowing HTML compatible MUAs to display the HTML portion only.
Mail Transfer Agent. This is a mail server used to send and receive mail. Examples of MTA’s include the IronPort A60, Port 25 Power MTA, StrongMail MTA, and Sendmail.
Mail User Agent. This interprets and displays email messages. Examples include Outlook, Eudora, and Mozilla Thunderbird.
The NANAS group is forum used by the anti-spam community to post information about messages sent to spamtrap addresses. Posting in NANAS usually indicate a practice issue. NANAS is only used for posting information, NANAE is the forum where the anti-spam community discusses postings in NANAS and other issues related to email abuse. The community can be fairly volatile – proceed with caution.
Request to be added to an email list
Request of a list member to no longer recieve messages
Reputation Service Provider (RSP)
A third party that provides accreditation and reputation services to senders and receivers. RSPs collect data about bounces, complaints and other user activity and aggregate it into a master database similar to the credit reporting system used for getting a loan. This data is used by receivers to decide which messages are spam or not and used by senders to monitor and improve their mailing practices. Examples of RSPs include Goodmail, Karmasphere, Lashback and SenderScore.
An authentication standard that goes slightly beyond SPF by looking at the headers of the message to determine the PRA, or purported responsible address.
Simple Mail Transfer Protocol, the standard used for sending and receiving mail.
Spam traps are addresses that have been posted by members of the anti spam and abuse communities to flush out spammers. If your list or your affiliates maintain lists that contain spam trap addresses, it usually indicates a serious issue with list acquisition practices. Spam trap addresses typically do not complain or request removal, so it is impossible to determine and remove them from a given list.
Sender Policy Framework. An authentication standard that specifies what IP addresses can send mail for a given domain. This is the easiest authentication standard to implement and is most widely used, but does not account for the visible headers in the message, such as the from and reply-to address.
Transactional Messages
Messages that are related to a service the user opted-in to and whose primary purpose is not to advertise a product or the use of a service. Typical examples of transactional messages include an order confirmation after you make a purchase or a bank statement.
The “list that shall not be named”.