Ad Networks vs. Ad Servers

iMedia Connection

Clearing up confusion over the function of these two industry essentials.

When I was a kid, my Uncle Charlie used to have a series of silly questions that made no sense. “Which is further, Miami or by bus?” “Do you walk to school or carry your lunch?” and my all-time favorite, “What’s the difference between a duck?” The answer to any of these questions was, “A violin, because a vest has no sleeves.”

To those of us who’ve been in the business awhile, the question, “What’s the difference between an Ad Network and an Ad Server?” is akin to one of Uncle Charlie’s silly questions. However, there is a relationship between the two and, for the purposes of this section of iMedia, it’s worthwhile to provide an overview of each.

An Ad Network is a group of Web sites which can be purchased through a single sales entity. It could be a collection of sites owned by the same publisher (e.g., AOL, CNN, Sports Illustrated, etc. are all owned by AOL/Time Warner) or it could be an affiliation of sites sharing a rep firm (e.g., Burst, HerAgency, Max each represent a collection of smaller “second tier” sites). In most cases, advertisers have the option to pick and choose from specific sites, to select a group of sites in a particular category or to run ads blindly across the entire network.

An Ad Server is a tool used by ad agencies and/or clients to facilitate ad trafficking and to provide reporting on ad performance. The value on the agency side is threefold:

Rather than distribute copies of each piece of creative to each publisher on a media buy, agencies can send a line of code to each publisher that calls up an ad directly from the ad server each time an ad is scheduled to run. The agency loads the creative to the server once and can modify rotations or add new units on the fly without needing to re-contact the vendors.
The ad servers provide a wealth of data including impressions served, ads clicked, click-through rate (CTR) and cost-per-click (CPC). Most of the ad servers also have the ability to provide performance against post-click activities such as sales, leads, downloads, or any other site based action the advertiser may want to measure. Furthermore, some of the ad servers can associate these post-click activities not only with site visitors who came via click, but also with site visitors who were exposed to the ads, but did not click. This is commonly known as view-through data.
The ad servers provide a consistent counting methodology across the entire campaign enabling the agency to gain an “apples to apples” comparison of performance across the entire media schedule.

Publishers and networks will also use ad servers to facilitate the serving of ads throughout their site(s).

It should be very clear from the above definitions that ad servers and ad networks are completely different things. So why the confusion?

With the exception of Atlas DMT, which was created by an ad agency, the rest of the ad servers were all designed by ad networks. The servers were originally used on the publisher side to distribute advertising across the various sites that made up a network. So, for example, DoubleClick was both an ad server and an ad network. However, the company has since sold off its ad network business perhaps sparing future generations from this confusion.

So getting back to the core question: What’s the difference between an ad server and an ad network? The answer, of course, is “a duck.”

Michael Comins is SVP, Director of Media Services for Insight Interactive Group (IIG). IIG offers a diverse line of strategic, tactical and technical interactive solutions aimed at online marketing for healthcare and pharmaceutical companies. Its focus in the healthcare industry allows the company to enhance the impact of individual brand programs with a deep knowledge of both the OTC and pharmaceutical marketplaces.