What is a display ad?
A display ad is the visual advertising that appears in a reserved space on a web page or in an app: the banner across the top, the box in the sidebar, the rectangle between paragraphs, the full-width unit on a news homepage. Display ads can be static images, animated HTML5, rich media that expands when touched, or short video. Most are sold through ad networks and programmatic exchanges, which place them in front of chosen audiences across thousands of sites at once.
Display is distinct from search, where ads answer a query, and from social, where ads sit in a feed. A display ad appears alongside reading or browsing, which is both its reach and its problem.
Why it matters
Why a display ad matters
Display offers scale and frequency at a low cost per impression. It is how a brand stays visible across the open web, follows up with people who visited its site and left (retargeting), and reaches audiences on publishers whose content matches its world. For awareness, and for reminding people who are already close to a decision, it remains one of the most efficient tools available. Display also reaches the long tail of the web: specialist publishers, local news sites and niche communities where a brand's audience gathers but where no single buy would be worth negotiating.
It is also the format people have learned to ignore. Click rates on standard banners are a fraction of a percent, and ad blockers remove many of them entirely. That makes the design of a display ad, and the choice of where it appears, more important than its sheer volume.
In practice
How a display ad works in practice
- 01
A display campaign is planned around an audience and a goal, then built as a set of sizes. The standard units (300 by 250, 728 by 90, 160 by 600 and 320 by 50 on mobile, among others) each need their own layout, because a message that fits a large rectangle will not survive a thin mobile banner. Designers build a master layout and adapt it, keeping the logo, the message and the call to action legible at every size.
- 02
The ads are trafficked through an ad server or a programmatic platform, which handles targeting, bidding and frequency caps. Performance is measured on viewability, clicks, view-through conversions and, for brand campaigns, lift studies. Creative is rotated before it fatigues, and placements that deliver impressions nobody sees are cut.
Watch out
What people get wrong about display ads
Cramming the page into the banner. A display ad has about a second of attention and a few square inches; it can carry one idea, one image and one action, and every extra element makes all of them weaker. The other mistake is judging display on clicks alone. Many people who see a display ad never click it and still search for the brand later, so view-through and lift tell a truer story than click-through rate. A third is ignoring where the ads actually appear. Without brand safety controls and regular placement reviews, display budgets drift toward low-quality sites built to harvest impressions.
