Glossary
Display advertising glossary
Every term we use across the site, defined in one line. Current on the 2025 cookie reversal, the MRC viewability standard, and the IAB banner formats. No jargon left unexplained.
Core programmatic terms
- Programmatic advertising
- Buying and selling ad space through automated auctions instead of manual insertion orders.
- RTB (real-time bidding)
- The per-impression auction that clears in roughly 100 milliseconds as a page loads.
- DSP (demand-side platform)
- The buyer's tool for bidding across exchanges, for example DV360 or The Trade Desk.
- SSP (supply-side platform)
- The publisher's tool for packaging and selling ad inventory into exchanges.
- Ad exchange
- The marketplace where DSPs and SSPs meet and the real-time auction takes place.
- Header bidding
- A method that lets several SSPs bid at the same time rather than in sequence, usually as a first-price auction.
- PMP (private marketplace)
- An invite-only auction on curated inventory, accessed through a deal ID; higher quality than the open exchange.
- Deal ID
- The identifier that connects a buyer to a specific private or guaranteed inventory deal.
- Programmatic guaranteed
- Fixed inventory and price agreed with one publisher, bought through programmatic pipes for the workflow.
Targeting and inventory
- Retargeting / remarketing
- Showing ads to people who already visited your site or used your app, usually the most efficient display audience.
- Prospecting
- Reaching new audiences who have not engaged with your brand yet.
- Contextual targeting
- Placing ads against relevant page content rather than tracking individual users; works without cookies.
- Behavioural targeting
- Targeting based on a user's past browsing behaviour, historically reliant on third-party cookies.
- First-party data
- Data you own from your own site, app and CRM; the durable basis for targeting as signal erodes.
- Third-party cookie
- A cross-site tracking cookie. Kept in Chrome after Google reversed deprecation in 2025; blocked by default in Safari and Firefox.
- Frequency capping
- A limit on how often one user sees an ad, commonly 3 to 5 impressions per day for display.
Pricing and measurement
- CPM
- Cost per thousand impressions. Display CPMs commonly run $2 to $5 on the Google Display Network and $5 to $15 on private marketplaces.
- vCPM (viewable CPM)
- Cost per thousand viewable impressions; you pay only for impressions that meet the viewability standard.
- CTR (click-through rate)
- Clicks divided by impressions. Display CTR is low by design, around 0.46% on the Google Display Network.
- CPA
- Cost per acquisition, the media cost to win one conversion.
- ROAS
- Revenue divided by ad spend. Display retargeting commonly returns about 4.2x.
- View-through conversion
- A conversion that follows a viewable impression without a click; often where display return hides.
- Working-media share
- The proportion of spend that reaches a real person. The ANA found the average is only 43.9%.
Quality, safety and standards
- Viewability
- Whether an ad was actually seen. The MRC standard counts a display impression as viewable at 50% of pixels in view for at least 1 continuous second (2 seconds for video).
- IVT (invalid traffic)
- Bot and non-human traffic. Around 20% of raw impressions, but under 1% on verified, protected campaigns.
- Brand safety
- Keeping ads off content that would damage the brand, enforced with pre-bid filtering.
- Verification vendors
- Independent measurement firms such as Integral Ad Science (IAS), DoubleVerify and Moat.
- TCF v2.3
- The IAB Europe Transparency and Consent Framework version operative since February 2026, required by Google in the EU.
- IAB standard sizes
- The common fixed banner formats: 300x250, 728x90, 160x600, 300x600, 320x50 and 970x250.
- DCO (dynamic creative optimization)
- Assembling a banner at serve time from a product feed and audience signal to personalise it.
Want the longer version? Start with what programmatic advertising is, or see how the standards play out in improving display ad viewability.
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