Explainers | 13 min read

What is display advertising?

In this article, we answer the most common questions related to display advertising. What is it? How does it work? What are its key features? It is an introduction to an effective form of online advertising and why you should use it as part of your marketing strategy.

The display advertising questions we will answer include:

  1. What is a display or banner ad?
  2. Why is HTML5 the preferred display advertising format?
  3. How does display advertising work?
  4. How is display advertising published?
  5. What are the different types of basic display campaign?
  6. How do you measure display advertising?
  7. What makes a successful display ad?
  8. And finally… How can you go beyond the basics?

But our first question is simple: how did all begin?

1. What is a display or banner ad?

The first banner ad appeared on the web in 1994 and was a little rectangular ad for AT&T on the first version of wired.com. Years later, and trillions of ads later, the fundamentals of display advertising remain roughly the same.

A display ad, or banner ad, is the box or ‘banner’ on a website that stands out from the rest of the website and looks distinctly like an ad. For example, it often features a product image, brand, and call-to-action (CTA).

Display ads can range from simple static images and animations, to videos and interactive applications. But one thing remains the same: when clicked on by a viewer they link back to a company’s website, or a dedicated landing page.

They can come in many sizes but the most popular are:

Display advertising trends 2019 banner sizes

2. Why is HTML5 the preferred display advertising format?

A brief history: Flash, static and HTML5 banners explained

Static banners are the granddaddy of all display advertising, and are non-interactive display ads. Static banners are either .jpg, .pngs or.gif files.

Once, there was also Flash. It offered flexibility in terms of design and interactivity. However, security vulnerabilities, and the fact it required a browser plugin, saw big tech industry players  drop support for it.

Finally, in June 2016 Google stopped supporting Flash banner ads and it ceased to be a valid format. Instead another format, HTML5, was crowned the number one advertising format for display advertising – with static ads remaining as the dull older brother.

But why is HTML5 the preferred format for display advertising?

What is a HTML5 banner ad?

Put simply, a HTML5 banner is an ad that uses the same coding language used to design and control webpages. It applies the latest update of Hypertext Markup Language. HTML5 banners are therefore coded and updatable – and interactive – unlike static banners.

For example, within a HTML5 banner ad, text, images, video, and JavaScript are easily editable, much in the same way as any webpage. Thus basic HTML5 banner ads can be coded to automatically optimise to look perfect for every device and website.

HTML5 responsive banner ads

They are also ideal for publishing to multiple ad networks, and offer advanced display marketers the ability to track clicks, as well as upload live data. Thanks to its superiority as a coding language, HTML5 is the default option for creating and controlling display campaigns.

3. How does display advertising work?

Display advertising is relatively easy to implement as part of your marketing strategy. In fact, in its most basic form it is four steps:

Step 1: Design

Firstly, (ideally using a HTML5 ad builder tool) assemble image and text elements to create your first banner, or master creative.. The master creative acts as a template for all the sizes in your campaign.

The basic design principles for creating a good display ad are:

  • Colour that matches your brand identity and inspires the right emotion.
  • Copy that is readable and contrasts with your background.
  • High quality and relevant images.
  • Having a logo that is clear and stands out.
  • And of course, a call-to-action (CTA) button to drive clicks.

Today, even the most basic banner ad must contain these fundamental elements to engage a consumer.

Note: You can create banners from scratch but this a difficult and repetitive process. And requires both expert coding and design skills! Plus, producing a campaign manually takes a long time, as each banner must be individually coded and reproduced. It is not recommended.

Examples of good display ads:

Step 2: Scale

Next, mass produce, or scale-out your ads into the different ad sizes your campaign requires. A display advertising campaign requires a range of different sizes to be effective and work across multiple devices and screen sizes.

Unfortunately, when scaling, each ad must be made separately. It is not a simple job of copy and paste, nor dragging a box. Each HTML5 ad must be individually coded – sometimes specifically to work a particular ad network (more on those later…).

Manually, this repetitive task can take hours, or even days! However, today there is software available that automatically optimises and codes banners. The smart scaling feature of a creative management platform (CMP), such as Bannerflow, which uses learning algorithms to automate the scaling process, is the best practice option.  

It is also important not to neglect mobile formats. Research shows that consumers prefer to browse on mobile devices in their leisure time. Indeed, it is considered good practice to design banners mobile-first because of the design challenges of smaller banners.

Step 3: Publish

Finally, the most important part of a display campaign, publishing!

At this point, all your HTML5 banners must be optimised to the specific sizes offered by a chosen ad network or ad exchange. For example, here is a list of sizes offered by Google. If you base your display ads on these sizes, you can be sure that most devices will display your ads correctly when your ad is served.

Again, uploading display advertising individually is another repetitive task that it is worth avoiding. If you use a CMP to create your display ads you may benefit from direct integrations with ad networks and ad exchanges. Thus, you can publish and control ads at the push of a button.

Step 4: After publishing

Once you have published your displays ads your campaign does not end there. Indeed, for many marketer’s this only the beginning of their display strategies.

For example, it’s important to analyse the effectiveness of your campaigns. Measure campaign costs, conversion rates, and continually A/B test to determine what imagery and messaging is working for your brand.


The Bannerflow analyse and optimise page.

Remember! Do not forget to build a post-click landing page to link to. Studies have shown that creating a visual link between ads and landing pages creates a sense of continuity and improves results.

Note: Display campaigns often require more stages than the four steps we have reduced it to here. More advanced display campaign production requires smooth editorial collaboration, translation of campaigns in other languages, and ad scheduling – not to mention media buying, multivariate testing and optimisation of live ads!

Plus, without the tool and features of a CMP, production processes can be long and tedious.

4. How is display advertising published?

Publishing display advertising can be both simple and extremely complicated. The truth is it is well worth researching media buying strategies to find what best suits your marketing team’s needs.

Below are four basic forms of display advertising publishing that you need to know:

What is a display ad network?

A display ad network is the best way of reaching the publishers, or websites, you wish to advertise on.

Ad networks act as brokers, buying unsold ad inventory (ad spaces) – packaging websites together based on target audiences – and then selling these to advertisers.

However, be careful selecting an ad network. While, some ad networks are very selectiveabout the type and quality of publishers allowed in the network, others are decidedly less so.

What is an ad exchange?

An ad exchange acts as a trading floor where a display advertisers can buy ad inventory from multiple ad networks.

Through this stock exchange-like environment, a display advertiser can target a specific audience, when they want, at the lowest possible price for across the web.

AppNexus and Google Marketing Platform are just two examples of ad exchanges.

What is programmatic buying?

Programmatic display advertising is a way to automatically buy and optimise digital campaigns across ad exchanges. Rather than buying directly from publishers, you use artificial intelligence (AI) to make buying decisions for you.

Ad inventory buying takes place in milli-seconds – think how long a webpage takes to load. Therefore, it makes sense to replace human negotiations with machine learning and AI-optimisation.

Programmatic buying allows marketers, who to produce large quantities of advertising, to deliver more effective and measurable display ads – at scale. Growing in popularity, programmatic display advertising is set to become the default ad inventory buying and publishing option.

How do you publish with a creative management platform (CMP)?

A CMP, such as Bannerflow, allows advertisers to publish banners programmatically to a network or exchange of their choice. It really is as simple as pressing a button.

When publishing, each banner has its own unique ‘click tag’. A click tag is a URL that you provide to publishers in order for your banners to be shown.

Note: For more advanced display campaigns, many more steps may be required. For instance: retargeting, scheduling campaigns, or producing sequences of ads for dynamic creative optimisation (DCO).

5. What are the different types of basic display campaign?

Basic display advertising campaigns can be divided into four distinct categories:

Brand awareness:

This is the most common use of display advertising. Brands pay for their display ads to appear across a variety of websites in a similar way to how they might place an ad on a billboard or in a newspaper. The aim is to get your brand name in front of as many relevant viewers as possible.

Campaigns such as these are often measured on reach and impressions.

Lead generation:

These campaigns are designed to attract direct interactions with the purpose of leading a viewer to your website landing page to complete a purchase or fill out a form. More advanced banners might include interactive elements such as product feeds, in-banner search, or live odds for instance.

These campaigns are usually measured by cost-per-acquisition (CPA) and click-through-rates (CTR).

Affiliate marketing:

Affiliate marketing is when a publisher (a websites owner) promotes a specific advertiser’s, or affiliate network’s ads in exchange for a commission on every sale or conversion that comes from that ad.

Display ads made for affiliate campaigns encourage click-through in ways that ordinary display ads do not. For example, obvious page placement, extremely attention-grabbing design, and unique enticing offers.


Retargeting is a marketing technique where you present a display ad to a user based on their previous behaviours on your website. The focus is about bringing consumers back to where they have shown interest and performing an action.

For example, it could be converting a viewer into a regular visitor or customer.

Note: Please be aware that there are many more advanced types of display advertising campaign strategy. For example, user journey retargeting, dynamic creative strategies, as well as dynamic creative optimisation.

6. How do you measure display advertising?


Measuring the success of your display advertising depends on the types of campaigns you are running and your chosen KPIs.

The metrics for display advertising measure how often your ad is seen, how effective is it at catching the eye, and whether your ad brings in revenue for your business.

Here is a brief guide to different display campaign metrics:


Impressions represent the number of times an ad appears on a web page. An impression is simply a record of views.


This metric demonstrates how many people see your ad. It shows the number of unique views a particular ad receives.


Usually displayed as a percentage, the engagement rate shows how many people interact with an ad. This could be something as simple hovering over an ad, or more complex, like filling in a search-banner.

Click-through rate (CTR):

The total number of people who click on your ad after seeing it.

Cost-per-click (CPC):

Total cost divided by the number of conversions from visitors coming from your ads.

Cost-per-acquisition (CPA):

Your overall campaign spend divided by the total number of conversions.

Return on investment (ROI):

The difference between the total revenue generated from your campaigns and total cost of running it in order to calculate the net profit.

Post view conversion:

When a user doesn’t click on a display ad but is influenced by it and returns to a site and then proceeds to convert.

Post click conversion:

When a user clicks on a display ad and proceeds to convert on a site.

7. What makes a successful display ad? Our take…

Creating that perfect banner is still one of the important parts of display advertising.

We spoke to Bannerflow’s Head of Customer Success, Emil Chroona, as well as our in-house display advertising experts, Joakim Allard and Ján Juriček, to understand what it takes to make a high performing display campaign:

Have design continuity across your campaigns

“First of all, it’s important to make sure your ads connect with your overall digital strategy – campaigns that have continuity across formats are far more likely to be successful.

What is more, the ads we see with CTR rates above 0.2% really encourage interaction without interfering on design, this can be something as simple as a call-to-action button to a search in-banner.”

Emil Chroona, Head of Customer Success at Bannerflow.

Nova sketch best display ad campaign

Animations and interactivity grab attention

“Use of animation is key to making your display ad stand out. It doesn’t have to be much but even small animations give your ad a better chance to engage the attention of a consumer.

Letting people interact with your digital display ads will also increase your CTR. For example, you could add a HTML5 interactive element (known as widgets at Bannerflow) that allows the user to fill in an order form right in the ad.”

Joakim Allard, Product Specialist at Bannerflow

Shorten the conversion funnel

“Shorten the conversion funnel by enabling selection in your ads. By using HTML5 widgets you can cut unnecessary steps of the conversion funnel on your website and redirect users straight to the product or plan they’re interested in.

Plus, if you use interactive elements that will only show when clicked on or hover over, you can also keep your ad design nice and clean.”

Ján Juriček, Product Specialist at Bannerflow

8. How do you go beyond the basics?

Display advertising is a vast topic and moving beyond the basics requires information that a single blog couldn’t possibly hope to cover.

Here are just some of the more advanced things you can do with display advertising:

Next steps

When used correctly, display advertising is an effective way of reaching consumers. It offers campaign strategies and tactics that marketing teams simply cannot ignore.

Plus, with the right tools, it can be an easy process too. A creative management platform, or CMP, is now the default way to produce advanced display advertising, in-house.

If you would like to find out more about how your marketing team can benefit from the unique features of a CMP, then get in touch, or apply for a demo.

Click below to watch our webinar on the future of display advertising, in partnership with MarTech!

Download the video about the future of display advertising

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