Ad Network

Written by Cobus van der Westhuizen, reviewed by Wynand van der Westhuizen, fact-checked by Lenata Oosthuizen. Last reviewed July 2026. Editorial policy.

What Is an Ad Network?

An ad network is a technology platform that connects advertisers with a collection of publishers, allowing ads to be displayed across multiple websites or apps through a single buying relationship.

Before programmatic advertising became dominant, ad networks were the primary way digital advertising inventory was bought and sold outside of direct publisher deals.

The network aggregates available space from its publisher members, classifies it by audience, content type, or geography, and offers it to advertisers as packages or targeting segments.

The business model of most ad networks involves buying inventory from publishers at a lower rate and reselling it to advertisers with a margin added. This is different from an ad exchange, where buyers and sellers transact directly in real-time auctions with transparent pricing.

Ad networks often operate with less transparency: advertisers may not always know exactly which publisher sites their ads appear on unless they opt into a whitelist arrangement.

That said, ad networks remain valuable for several reasons. They simplify media buying, particularly for businesses without dedicated programmatic teams. They often provide contextual and demographic targeting that suits specific campaign objectives.

And many networks specialise in particular niches or formats, such as video networks, mobile app networks, or B2B publisher networks, giving advertisers access to concentrated, relevant audiences that would be difficult to aggregate independently.

The most widely used ad network for South African businesses is the Google Display Network (GDN), which provides access to over two million websites and apps.

The GDN operates through Google Ads, making it accessible even to small businesses in Johannesburg, Pretoria, Cape Town, and beyond without requiring a specialist programmatic buyer.

South African businesses also use Meta's Audience Network for mobile app advertising, extending their Facebook and Instagram campaigns to third-party apps.

Ad Network In Practice

The two scenarios below are illustrative examples, not Juicy Designs client results. The figures indicate the scale of effect that ad network work typically produces, so treat them as indicative rather than measured.

Picture a Cape Town-based travel company wanting to promote domestic holiday packages. It might use the Google Display Network to reach users browsing South African lifestyle and news sites.

Through a single campaign setup in Google Ads, it could target users by interest (travel enthusiasts, outdoor activities), geography (major metros), device type, and remarketing lists of past website visitors.

The GDN would handle the placement across its publisher network without the advertiser needing to negotiate individual deals with each site.

Or consider a B2B software company selling into the South African market. It might use a specialist tech publisher network to target IT decision-makers on industry-specific sites.

Specialist networks typically charge higher CPMs than broad networks, but the audience quality is usually higher, which would tend to produce better conversion rates for products with long sales cycles.

The choice of network should always be informed by where the target audience actually spends time online, rather than which network offers the lowest cost per impression.

What an ad network is

An ad network is a service that connects advertisers with publishers (websites, apps and other places that show ads), aggregating advertising space from many publishers and selling it to advertisers, so that advertisers can place ads across a network of many sites and apps rather than dealing with each publisher individually. Ad networks act as intermediaries in the display and programmatic advertising ecosystem: they gather the available ad inventory (the ad spaces) from numerous publishers and offer advertisers the ability to run ads across that collective inventory, often with targeting options, so an advertiser can reach audiences across many websites and apps through a single network. The most prominent example is the Google Display Network, which lets advertisers show display ads across a vast network of websites, apps and Google properties that partner with Google to show ads. Other ad networks exist across the industry, some general, some specialised by content type, audience or region. Ad networks enable display advertising at scale, letting advertisers reach broad or targeted audiences across many properties, and letting publishers monetise their sites and apps by making their ad space available through the network. They are part of the broader ecosystem that also includes ad exchanges and programmatic platforms, which have made buying and selling ad inventory more automated and data-driven. Understanding ad networks matters because they are how much display advertising reaches audiences across the web and apps: rather than advertising on one site at a time, advertisers use ad networks (like the Google Display Network) to place ads across many properties, so knowing what an ad network is helps a business understand how display and programmatic advertising works and how to reach audiences across the wider web through advertising.

Ad networks for businesses

For a business considering display advertising, ad networks (chiefly the Google Display Network, given its scale and accessibility) offer a way to reach audiences across many websites and apps, and whether and how to use them depends on the goals and the care taken in targeting. The value of ad networks is reach and targeting at scale: through a network like the Google Display Network, a business can show display ads across a vast range of sites and apps, targeting by audience interests, demographics, topics, placements, or remarketing to past visitors, which is useful for building awareness, reaching relevant audiences broadly, and retargeting. Display advertising through ad networks is generally more about awareness, reach and retargeting than the high-intent capture of search ads, so it suits goals like brand awareness, reaching potential customers as they browse, and staying in front of people who have visited your site (remarketing), rather than capturing people actively searching to buy (which search ads do). The key to using ad networks well is careful targeting and management: because the reach is broad, untargeted display advertising can waste budget showing ads to irrelevant audiences or on poor placements, so using the network's targeting to reach relevant audiences, excluding poor placements, and using remarketing to focus on warm audiences, makes display advertising far more effective, whereas broad, unmanaged display spend often disappoints. Strong, relevant ad creative matters too, since display ads must earn attention amid content. For a South African small business, ad networks like the Google Display Network can be worthwhile for awareness and especially remarketing (showing ads to people who have already visited your site, which is often among the most effective display uses), and for reaching relevant audiences across the web, provided the targeting is careful and the goals are appropriate (awareness and reach, or remarketing, rather than expecting search-like high-intent conversions). Whether a small business should use ad networks depends on its goals and budget: for awareness and remarketing with careful targeting, they can add value, but they should be used deliberately, with good targeting, relevant creative, and realistic expectations, rather than as an untargeted spend. The practical guidance is to use ad networks (like the Google Display Network) where awareness, broad reach or remarketing suit the goal, with careful targeting and management to ensure the reach is relevant and the budget is not wasted, which is how a business gets value from advertising across the wider web through ad networks.

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