A method of creating relevant email or Web content based on a user's behavior, including opens and clicks, pages visited or conversions. See also Targeting.

A list of domains or IP addresses that an organization has deemed to be owned by spammers and thus should be blocked.

A limited-scale Web site or page designed for collaborative content generation and frequent updating, also including reader comments on posted material.

A search formed by joining simple terms with AND, OR and NOT for the purpose of limiting or qualifying the search. If you search information on salmon fishing in Alaska, and your search also brings back information on trout fishing and diving in Alaska, the Boolean search "salmon AND fishing AND Alaska NOT diving" can narrow your search focus.

A message that is returned to the server that sent it. A bounced email is usually classified as either a "hard bounce," which indicates a permanent failure due to a non-existent address or a blocking condition by the receiver, or a "soft bounce," indicating that there is a temporary failure due to a full mailbox or an unavailable server. Hard-bouncing message should not be retried. Soft-bouncing messages can be retried one or two times.

Total number of failed (bounced) messages divided by total number of emails sent.

A line of characters in an email message that indicates to the email client that different parts of the message should be "read" differently.

The headline-like text that runs in the bar across the top of the browser window, typically naming and describing the page, often optimized for keyword search or navigation.