Ad-servers - Part II

In this article we’ll take a close look at how ad-servers actually serve the ads that the user sees.

The first step, our imaginary company Weightloss (WL) has to place its ads into its ad-server. The ad-sever then creates tags. The tags give the following details –

Ad size

Where the ad can be located on the web page

The tags are sent to the publisher alongwith information on WL’s campaign like –

Number of times a day it has to appear also called frequency cap. An ad can be 1/24 frequency capped, meaning it appears once in 24 hours on a particular PC, or 2/24 meaning it appears twice in 24 hours etc

Demographics of the targeting i.e. should the ad be targeted to men/women of a certain age group, who have specific interests ( interested in golf, gardening..)

Geography to which it is targeted – Campaigns could be targeted to the UK, US, Germany….

Specific time during the day when the ad should appear

All of WL’s campaign instructions are now loaded onto our imaginary newspaper the England Journal ‘s(EJ) ad-server. The ads themselves reside on WL’s ad-servers. The EJ similarly receives tags from other advertisers as well.

What happens next?

Suppose a user enters the website URL of The England Journal onto their PC, the EJ website is displayed on his/her PC. What is loaded on the user’s PC is content… A logical question that arises is – How does an ad get loaded onto a user’s browser? The user’s browser follows instructions it receives from The EJ, which in turn directs to get an ad from the EJ ad-server.

The EJ server in turn instructs the WL ad-server to serve an ad. The WL ad-server then has to figure out which ad to show. A cookie helps the WL ad-server in this process. When the EJ ad-server sent the user’s PC content, it also sent it a cookie. A cookie is a small piece of software that travels between the EJ ad-server and the WL ad-server. A cookie identifies a browser. A cookie controls the number of times the user sees an ad, has user information like age, sex , preferences etc.

The EJ ad-server selects the ad and serves it on the user’s PC. The ad selected is based on user information provided by the cookie. When WL’s ad-server sends an ad to the User’s PC, it also sends it a cookie which allows it to identify the user’s browser. This allows WL’s ad-server to track number of times an ad is shown on the user’s PC.

The process of serving an ad, though happens in a few seconds, is a fairly involved process. This process is completely managed by the different ad-servers in the network without any human intervention whatsoever. Amazing isn’t it?