E-mail campaign
Advertising campaign distributed via e-mail.

Expandable banner
Banner ad, which can expand to as large as 468x240 after a user clicks on it or after a user moves his/her cursor over the banner (Source: IAB)
Floating ad
Ad that appears within the main browser window on top of the web page's normal content, thereby appearing to "float" over the top of the page (Source: IAB)
Frequency capping
Limiting the number of times an advertisement is delivered to a user within a specific time frame.

Geo targeting
Serving of ads to a particular geographical area.

Impressions
The number of times a creative is displayed, either on a web page or in a separate browser window as a pop-up or pop-under advertisement. A single page view can have more than one impression if there is more than one ad placed on the page, or if dynamic ad rotation is used.

Internet Protocol address (IP address)
A unique number that identifies each machine connected to the Internet. The IP address takes the form of four numbers separated by dots.

Interstitial
Ad that appears between two content pages; also known as transition ad, intermercial ad, splash page and Flash page (Source: IAB)

Inventory
The ad space available for sale on a Web site or other media.