The disreputable and often illegal act of falsifying the sender email address to make it appear as if an email message came from somewhere else.

Short for Secure Sockets Layer, a protocol developed by Netscape for transmitting private documents via the Internet. SSL works by using a public key to encrypt data that's transferred over the SSL connection.
Both Netscape Navigator and Internet Explorer support SSL, and many Web sites use the protocol to safely transmit confidential information, such as credit card numbers.

A tall, thin online ad unit.

Colour reproduced by using ink of that colour, not created by the four-colour process.

Backlit advertising structure located at strategic points in shopping malls; usually two or three-sided, includes directory format.

(Radio): When two or more Radio stations broadcast the same programs and same commercials at ALL times, and use only one traffic system, they are said to be simulcast.
If two or more stations broadcast only a portion of their day together, but are different at other times, they are considered to be "partially simulcast," but would require two time order or traffic sections to schedule programs or announcements during the times when they have separate programming.

Refers to Poster panels located on train, subway or commuter rail platforms; several sizes available.

In newspaper, a way of measuring advertising space.