Above the Fold Refers to the top portion of an e-mail that can be viewed through the preview pane (most common in Microsoft® Outlook). Items placed "above the fold" can be viewed without the user fully opening the e-mail.

Acquisition List A list of prospects rented from a broker or vendor with a targeted group of recipients to whom an e-mail campaign can be sent, driving them to register on a website. (Note: All rented lists should be a certified opt-in, permission lists.)

Address Book Whitelisting The process of an e-mail recipient adding a company's e-mail address and/or domain name to their personal e-mail address book. This helps to prevent the inadvertent filtering of e-mail from trusted senders.

API (open) Application programming interface refers to the statements a programmer can use to manipulate the behavior of an application.

Bandwidth The amount of data a connection is capable of moving. Bandwidth is generally measured in bits per second. A T1 line can move 1.5 million bits of data per second and is referred to as having "1.5 megabits" of bandwidth.

Bayesian or Statistical Filter Bayesian or statistical spam filters assign mathematical probabilities to e-mail based on the assumption that some words, phrases and other characteristics occur more frequently in UCE and other words occur more frequently in legitimate messages.

Blacklist A blacklist is a list of IP addresses of mail servers that are suspected of sending unsolicited commercial e-mail. Blocking E-mails that are blocked are prevented from reaching the inbox, either by an Internet Service Provider or a mail filter.

Bonded senders Organizations that, for a fee, certify an e-mail sender as a "good guy" who conforms to permission marketing standards.

Campaign E-mails that go out to a rented or small house list at varying schedules with multiple creative treatments and content.

Can-Spam Act Otherwise known as "Controlling the Assault of Non-Solicited Pornography and Marketing Act." Enacted in 2004, this is the first piece of federal e-mail marketing legislation in the United States. It prohibits deceptive e-mail marketing practices, requires a functional opt-out method and prohibits e-mail address harvesting and automatic address generation.

Challenge/Response Filtering A filtering system in which the sender's e-mail address or domain name must be listed in the recipient's address book in order for e-mail to be delivered directly to the inbox. All other mail is filtered into a separate folder. The system then sends an automatic message, or "challenge" to the senders who don't make it to the inbox. The "challenge" requires the sender to perform a task that can't be automated.

Click-through Rate The number and percentage of recipients who clicked on a particular URL included in an e-mail.

Content Based Filters A UCE filtering product that sorts messages based on simple strings or keywords located in the header and message body.

Conversion Rate The number of prospects who purchased a product or service in an e-mail marketing campaign.

Deliverability The term deliverability addresses a series of processes concerning the intricacies of e-mail delivery. Deliverability can refer to inbox delivery, e-mail filtering, bounced messages and readability of the message to name a few.

Double Opt-in The act of asking subscribers (recipients) to ask for campaigns twice. This is typically done when the initial request is made and a follow up e-mail is sent to the subscriber asking them to reply to the message to opt-in again.

False Positive Occurs when a legitimate permission-based e-mail is incorrectly filtered or blocked as spam. HTML-sniffer Technology embedded in e-mail software that enables it to determine if recipients can receive HTML content.

Hard Bounce/Soft bounce A hard bounce is a message whose delivery failed for a permanent reason, such as "no such address;" a soft bounce is a message whose delivery failed due to a possibly temporary condition, such as an offline mail server or a full mailbox.

Headers contain information about the e-mail and the route the message has taken across the Internet. Headers include sending and receiving mail servers, dates and times, as well as recipient's information ("to" line), the sender information ("from" line) and the subject line. The Can Spam Act (see above), makes it illegal to forge or conceal information contained in the header. Heuristic Filters Heuristic filters attempt to identify UCE using reiterative guesswork and past experience, to establish filtering rules.

Honeypotting Occurs when planted e-mail addresses find their way into permission e-mail marketers' lists. ISPs and spam-fighters place these addresses on the web waiting for them to be harvested by a spammer or unreputable list creator. If a legitimate e-mailer purchases a list containing a honeypot, all mail going to the ISP using the honeypot is blocked, even if recipients opted in.

Internet Service Provider (ISP) A company which provides other companies or individuals with access to, or presence on, the Internet. ISP's control the delivery of e-mail to their members.

Landing Page When an e-mail recipient clicks-through to a site, this is the page they should see first. Making sure this page resembles the offer in the e-mail campaign is the first step toward getting recipients to click "buy." A landing page consistent with the e-mail campaign also avoids confusing the recipient.

List Sampling Segmenting a customer list to determine how different population segments respond to various marketing messages.

MTA Mail transfer agent is a mail server program, not to be confused with a mail reader program. Generally, humans do not interact with MTAs-MTAs interact with each other, e.g., through the Internet. Mailer Daemon The e-mail address "MAILER-DAEMON@...." is in common use among older UNIX MTAs. If an MTA generates an e-mail (such as a bounce report), it uses MAILER-DAEMON as the "from" address.

Message Testing Sending several unique messages to customers in order to gauge differences in response rates. Multipart-Alternative Sending both text and HTML content to a recipient, allowing the e-mail client or browser to display the optimum type of contents.

Open rate Also known as read rate. This is the rate of e-mails opened in any given e-mail marketing campaign and the percentage against the total number of e-mails sent.

Opt-in (or subscribe) Requesting to receive information from a company via e-mail. Many companies offer more than one type of e-mail campaign for opt-in.

Opt-out (or unsubscribe) The act of removing oneself from a list or lists so that specified information is no longer received via e-mail.

Passed Parameters The act of including arbitrary subscriber information in a redirect URL. This allows you to provide web applications that can pre-populate form values requiring the subscriber to do less typing.

Permission Based E-mail The opposite of spam. It's sending e-mail to recipients who have given permission and is the only way for reputable companies to effectively market their products without offending recipients.

Program An ongoing e-mail communication to an in-house subscriber database using regular scheduling, consistent creative treatments and relevant content.

Query A subset of records from your database. If your database contains people from all over the U.S. then a query might specify, "males aged 18 or older who live in the southeastern United States."

Readability An e-mail client's correct rendering of HTML e-mail.

Read Rate Also known as open rate. This is the rate of e-mails opened in any given e-mail marketing campaign and the percentage against the total number of e-mails sent.

Redirect URL A URL (uniform resource locater) is a clickable link located in e-mail message contents that takes the recipient to a designated Web page. If a marketing service or software is used, the application will collect response information and redirect the recipient to the appropriate Web page.

Relational Database A software application useful in storing information, such as Oracle, Microsoft SQL Server or IBM DB/2.

Remarketing Using past campaign or click-through information to target recipients for follow-up e-mail campaigns.

Reply-to Address This is the address to which all replies are routed when an e-mail recipient replies to a message.

Retention List An in-house client list used to market products and services and establish valuable relationships with clients.

RFC Compliant The Requests for Comments (RFC) document series is a set of technical and organizational notes about the Internet.

Rule-based Filters A type of UCE filter that looks at each e-mail entering the network and accepts or rejects it based on user-defined rules. One common rule is referred to as expression matching or text analysis, which blocks e-mails containing certain words in the body or headers of the message.

Spam or Unsolicited Commercial E-mail (UCE) E-mail sent to someone who has not requested to receive it.

MailFrontier is a common brand of e-mail filter. It uses a rule base among other methods to identify spam based on characteristics that are common in unsolicited commercial e-mail.

SQL Query SQL (Structured Query Language) is an English-like language for retrieving data from a database by typing. For example, to get an e-mail address from a company database, the query might be: SELECT E-MAIL_ADDR FROM EMPLOYEES WHERE LAST_NAME = 'Johnson'

Subscriber A recipient of a permission-based e-mail marketing communication. Subscriber Data Information collected about recipients of a permission-based e-mail marketing communication. Usually stored in a database, this data can be comprised of demographic and psychographic information.

Unsolicited Commercial E-mail (UCE) Otherwise known as spam, UCE is e-mail sent to someone who did not requested to receive it.

Viral Marketing A marketing strategy that encourages individuals to pass on marketing messages to friends and colleagues, creating exponential growth in the message's exposure and influence. Viral marketing is common with e-mail because of the ease of forwarding messages.

Volume blocking Occurs when a mailing containing a large number of obsolete or bouncing e-mail addresses reaches the ISP's bounce threshold and causes the rest of the mailing to be junked.

Web Insert Takes a Web page or Web application and pushes its contents into an e-mail when the recipient opens it. Used for surveys, banner ads and e-statements so marketers do not have to duplicate Web material in e-mail messages.

Whitelist Whitelists are groups of recognized senders, who recipients want to receive e-mail from. Whitelisting is the opposite of blacklisting.

X-Mailer This is a standard e-mail header. E-mail contains a set of headers and a body. The body is text that is read; the header is all other fields including "From," "Subject," "Reply-to" and "Date." One of those fields, the X-Mailer, tells what program was used to create the e-mail. For example, "X-Mailer: Microsoft Outlook 5.2.7.2 build 1322." XML eXtensible markup language.

XML is a simple language for the transfer of data from one point to another. The most common subset of XML is HTML