1. Online terminology

2. Your guide to common online advertising terminology

3. Ad impression Each ad being served into a webpage is an impression. A page may have more than one ad impression. Banner A long, horizontal online advert usually found running along the top of a web page in a fixed placement. Click Every time someone clicks on an online advertisement and goes through to a client website, this is counted as a click. Click-through rate (CTR) For any given online ad, the CTR is the number of clicks divided by the number of page impressions.

4. CPA (cost per acquisition), CPO (cost per order), ROI (return on investment) These are all common terms used to measure the success and performance of online campaigns. CPM The cost per thousand ad impressions delivered. Leaderboard A horizontal online advert, similar to a banner (see above), but larger. MPU (message placement unit) A square advert usually found embedded in a web page in a fixed placement. An MPU is a flexible ‘blank canvas’ in which it's possible to serve flat content or something more interactive, as desired.

5. Overlay Online advertising content which appears over the top of a web page. It uses interactive and audio-visual elements to give richer content and a richer experience for the user when they interact with the advert. Page view (or page impression) A single viewing of a web page. Page view statistics are often used to measure the popularity of a site. Popup An online advert that appears on a specific page and ‘pops up’ as a separate element.

6. Pre-roll The adverts shown before or while an online video loads. There can be more than one, and they currently average 21 seconds in duration. Skyscraper A long, vertical online advert usually found running down the side of a web page in a fixed placement. Sponsorship This can be arranged as part of an integrated deal or for an individual site, section or platform. Super sky A vertical online advert, similar to a skyscraper (see above), but larger.

7. Tenancy (or fixed cost) A one-off fee charged for the duration of an ad campaign. Unique users Measured as each unique person who visits a site in a 30-day period.