To state the obvious, researching, finding, and buying digital ad space is a time-consuming process. In fact, an article by the Wall Street Journal compares it to “pulling out weeds online.”

But what if there was a middleman who could connect advertisers to websites that are seeking advertisers (and vice-versa)? Enter the ad network.

Let's learn more about ad networks, how they work, and the best networks for digital marketers.

The chief function of ad networks is to collect unsold ad inventory from online publishers and match them with advertisers looking for ad spots. This makes it seamless for both sides to interact and, ultimately, come to a deal.

The benefit of using an ad network depends on which side you fall. For publishers, it helps to secure buyers for unsold ad space, although the revenue is typically less than what they could earn from direct sales. For advertisers, it helps to find inventory that fits their audience and budget.

It's important we make a distinction between ad networks and ad servers. While both operate as advertising technology, they serve two distinct purposes.

An ad server is used by both ad networks and advertisers to run, track, and manage advertising campaigns. An ad network is also an advertising technology, but it's used exclusively to broker buys between publishers and advertisers.

Different Types of Ad Networks

If you need to find an ad network that fits your particular audience or industry, odds are you'll have no problems finding one. There's an overwhelming amount of ad networks for different topics, audiences, and formats.

Here are four main types:

• Vertical networks: Ad networks that are topic-specific, such as fashion, automotive, or business.
• Premium networks: Ad networks that offer inventory from popular publishers.
• Inventory-specific networks: Ad networks that provide a specific type of ad inventory, such as video or mobile.
• Targeted networks: Ad networks that offer specific targeting capabilities that are built into the ad server.

So how much does using an ad network cost? Like most online advertising, it depends.

Some ad packages have a fixed rate, while other options may charge you on a cost-per-click (CPC) or cost-per-thousand impression (CPM) basis. Other times, an ad network will bring inventory to auction and use real-time bidding (RTB) technology to match ad impressions with the highest bidder.

How do ad networks work?

Ad networks are a powerful tool for both advertisers and publishers. But exactly how do they work? Here's a traditional model of an ad network — but keep in mind that because of evolving technology, these steps are ever-changing.

1. To start, ad networks aggregate a large number of publishers with available inventory.
2. Meanwhile, the advertiser creates a campaign using the ad network's campaign panel. When creating the campaign, the advertiser fills out details about the budget, target audience, and more.
3. On the publisher side, they install the ad network tags on their website.
4. When a match occurs between an advertiser's campaign and a publisher's supply, the ad details are sent to the publisher. The ad network earns money by taking a cut of the ad revenue, or by marking up inventory before selling it.
5. Once the ad is live, the advertiser can track and manage its performance in the ad network's campaign panel.

Ready to give ad networks a try? Here's a list of the 9 best ad networks for both advertisers and publishers.

Best Ad Networks

1. Google Adsense

When it comes to ad networks, Google Adsense is one of the oldest — and largest — networks. And with its great reputation and sophisticated technology, it's not going away anytime soon.

Google Adsense can publish ads in various formats and provide super detailed targeting options, like behavioral targeting. But be warned, Google AdSense holds its advertisers to a high standard of quality, so prepare to follow the rules.

2. Media.net

Media.net is one of the most distinguished ad networks on the web, making it a popular alternative to Google Adsense. Some of its most well-known publishers include CNN, Forbes, and Esquire.

Bing and Yahoo power Media.net, exposing publishers to a large pool of both national and local advertisers. On the flip side, advertisers can leverage the ad network to create contextual ads across multiple inventories, including search, native, display, and mobile.

3. PopAds

PopAds is one of the leading ad networks specializing in pop-under ads. As a refresher, pop-under ads appear under an active window for desktop and mobile users.

PopAds offer instant approval and competitive CPM rates. And, unlike other ad networks, there's no minimum traffic requirement.

4. PropellerAds

Another heavy hitter in the ad network sphere is PropellerAds. PropellerAds offer a variety of ad formats, including display, native, pop-under ads, and push notifications.

PropellerAds unite publishers and advertisers through its Self-Service platform.

With the platform, you can create campaigns and see real-time reporting for your ads, making it easy to track and manage campaigns.

5. BidVertiser

BidVertiser is an attractive option for publishers — just take a look at its monetization model. In addition to earning money each time an ad is clicked, a publisher also earns a little extra when the click leads to a conversion, such as a sale for the advertiser.

BidVertiser also has a bidding system to ensure publishers secure the highest revenue for each ad impression.

6. Adcash

Adcash offers a number of ad formats and tools to help publishers monetize their traffic better. What's better, their technology can bypass those pesky ad blockers. With a clean interface and straightforward reporting tools, it's one of the most user-friendly ad networks on the market.

7. AdThrive

AdThrive is an ad network specializing in publishers in the lifestyle industry, including travel, food, and fashion. So, if you fall into one of these niches (or not, you can still join), you may thrive on this platform.

AdThrive follows a “creator-first mindset,” and part of the deal is guaranteeing payouts for publishers — meaning, even if AdThrive doesn't get paid by an advertiser, they will still pay you.

8. Amazon Affiliates

Amazon Affiliates is one of the leading affiliate ad networks on the web. As an affiliate, you can use link-building tools to direct readers to certain products. Here's how it works: If a visitor clicks on a native shopping ad and makes a purchase, you earn a commission.

It's also important to note that Amazon Associates has strict rules and policies, more than other ad networks.

9. Propel Media

Propel Media specializes in display and push ads. It's also one of the best ad networks for reaching a high-intent audience. Using intent-based technology, it can analyze customer intent and match it with highly relevant content in real time.

The right ad network can help advertisers reach their target audience and increase conversions. And for publishers, it's an effective way to secure buyers and fill ad inventory. However, there's an overwhelming amount of ad networks available, so carefully weigh your options.