Glossary
Ad tech, in plain words.
104 terms every publisher meets, each with a 1-minute video, a game to practise it and a Hindi version.
A
- A/B test (yield) A yield A/B test splits visitors at random between your current ad setup and a change, then compares revenue to show whether the change really helped. ▶ video
- Active View Active View is Google Ad Manager's viewability measurement. It reports which impressions were viewable under the IAB/MRC standard. ▶ video
- Ad density Ad density is the share of a page's height taken up by ads. On mobile, the Better Ads Standards treat more than 30% as too much. ▶ video
- Ad exchange An ad exchange is a marketplace that runs an auction for each impression, letting many buyers bid on many publishers' inventory. ▶ video
- Ad network An ad network gathers ad space from many websites or apps and resells it to its own advertisers, keeping a share of the money. ▶ video
- Ad pod An ad pod is a group of video ads played back to back in one break, like a TV commercial break, common in CTV and long-form video. ▶ video
- Ad refresh Ad refresh loads a new ad into the same slot without reloading the page, on a timer, after an event, or once the current ad has been viewable. ▶ video
- Ad request An ad request is the call a web page or app makes to an ad server or exchange, asking for an ad to fill one ad slot. ▶ video
- Ad seasonality (Q4) Ad seasonality is the yearly rise and fall in advertiser demand: CPMs usually climb through Q4's holiday season and drop in January. ▶ video
- Ad server An ad server is the software that decides which ad fills each slot, applying the publisher's rules for priority, targeting and price. ▶ video
- ads.txt ads.txt is a public text file at the root of a website that lists every company allowed to sell its ad inventory, and whether each is DIRECT or RESELLER. ▶ video
- app-ads.txt app-ads.txt is the ads.txt list for apps and CTV: a public file on the developer website naming every company allowed to sell the app's ad inventory. ▶ video
- Auto ads Auto ads is an AdSense feature that lets Google choose where and when to place ads on your pages, within limits you set.
B
- Behavioural targeting Behavioural targeting shows ads based on what is known about a person, such as browsing history or past purchases, rather than the page they are on. ▶ video
- Better Ads Standards The Better Ads Standards list the ad experiences readers find most annoying, such as pop-ups and auto-playing video with sound, that sites should avoid.
- Bid adapter A bid adapter is a plug-in that lets Prebid talk to one demand partner, turning its bid requests and responses into Prebid's format. ▶ video
- Bid shading Bid shading is when a buyer bids below its true value in a first-price auction, aiming to pay just enough to win. ▶ video
- Blocklist A blocklist is a list of ad categories, advertisers, buyers or keywords that a publisher or buyer refuses, so matching ads or pages are skipped. ▶ video
- Brand safety Brand safety means keeping ads away from content no advertiser will fund, and keeping harmful or unsuitable ads away from a publisher's readers. ▶ video
C
- Clearing price The clearing price is what the winning bidder actually pays for an impression. In a first-price auction it is the winning bid itself. ▶ video
- CLS (Cumulative Layout Shift) CLS (Cumulative Layout Shift) is the Core Web Vital that scores how much visible content jumps around while a page loads. 0.1 or less is good. ▶ video
- CMP (consent management platform) A CMP (consent management platform) is the tool behind a privacy banner: it asks readers for consent and passes their choices on to ad partners. ▶ video
- Contextual targeting Contextual targeting matches ads to the content of the page, such as its topic or category, rather than to what is known about the person reading it. ▶ video
- Cookie sync Cookie syncing links the ID one ad tech company stores for a browser with the ID another company uses, so both can recognise the same browser. ▶ video
- Core Web Vitals Core Web Vitals are Google's three page experience scores: LCP for loading, INP for responding to taps and CLS for visual stability. ▶ video
- CPM CPM (cost per mille) is the price an advertiser pays for 1,000 ad impressions. A $2 CPM means $2 for every 1,000 impressions. ▶ video
- CTR (click-through rate) CTR (click-through rate) is the share of ad impressions that get clicked: ad clicks ÷ ad impressions × 100.
- CTV (connected TV) CTV (connected TV) is streaming video watched on a television through a smart TV, streaming stick or console, with ads served over the internet. ▶ video
D
- Deal ID A deal ID is the code that ties a programmatic bid to an agreed deal, so the SSP, DSP and ad server all apply the deal's terms. ▶ video
- DIRECT vs RESELLER DIRECT and RESELLER are the ads.txt relationship values: DIRECT means you control the seller account yourself, RESELLER means a partner sells for you. ▶ video
- Direct-sold inventory Direct-sold inventory is ad space a publisher's own sales team sells to an advertiser under a contract, usually at a fixed price. ▶ video
- Domain spoofing Domain spoofing is selling ad inventory under a better site's name than the one the ad really runs on, so buyers pay for traffic they did not get. ▶ video
- DSP (demand-side platform) A DSP (demand-side platform) is software that advertisers and agencies use to bid on ad impressions across many sites and apps. ▶ video
- Dynamic allocation Dynamic allocation lets Google Ad Exchange compete in real time with Ad Manager line items, so each impression can go to the highest bidder. ▶ video
- Dynamic floor A dynamic floor is a minimum bid price that updates automatically from bid data, instead of being typed in once and left alone. ▶ video
E
F
- FAST channels FAST channels are free ad-supported streaming TV: scheduled, TV-style channels delivered over the internet and paid for by ads, not subscriptions. ▶ video
- Fill rate Fill rate is the share of ad requests that return an ad: impressions ÷ ad requests. 8,500 impressions from 10,000 requests is 85%. ▶ video
- First-party data First-party data is information a publisher collects directly from its own audience, such as sign-ups, logins, reading history and survey answers. ▶ video
- First-price auction In a first-price auction the highest bid wins and pays exactly what it bid. Google Ad Manager has run one since 2019. ▶ video
- Floor price A floor price is the lowest CPM a publisher will accept for an impression. Bids below the floor are rejected. ▶ video
G
- GIVT and SIVT GIVT and SIVT are the MRC's two types of invalid traffic: general IVT, caught with lists, and sophisticated IVT, which needs advanced analysis. ▶ video
- Google Ad Manager Google Ad Manager is Google's ad server for publishers: it decides which line item, deal or auction bid fills each ad slot, and it includes Ad Exchange. ▶ video
- Google AdSense Google AdSense is Google's ad network for publishers: it finds advertisers, runs the auction, places the ads and pays you a share of the revenue. ▶ video
- GPP (Global Privacy Platform) GPP is IAB Tech Lab's single privacy string for many laws, such as US state opt-outs. Once Global Privacy Platform, it is now Global Privacy Protocol. ▶ video
H
- Hashed email A hashed email is an email address turned into a fixed code by a one-way hash, so it can be matched for advertising without sharing the address itself. ▶ video
- hb_pb hb_pb is the Prebid key-value that carries a bid's rounded price bucket to the ad server, for example hb_pb=2.10. ▶ video
- Header bidding Header bidding asks many demand partners for bids at the same time, before the ad server decides, so they all compete on price. ▶ video
- Header bidding wrapper A header bidding wrapper is the code that runs the header auction on a page, managing bidders, the timeout and the hand-off to the ad server. ▶ video
- House ad A house ad is a publisher's own promotion that fills an ad slot when no paid ad serves. It earns nothing but avoids a blank space. ▶ video
I
- Impression An impression is one ad served once on a page or in an app. Most display ads are priced per 1,000 impressions (CPM). ▶ video
- In-app bidding In-app bidding lets ad networks bid on each app impression at the same time, so the highest bid can win instead of the first network in a fixed order. ▶ video
- Interstitial ad An interstitial ad covers the full screen at a natural break, such as between pages or game levels, and the user closes it to carry on. ▶ video
- Invalid traffic (IVT) Invalid traffic (IVT) is ad clicks or impressions that do not come from genuine human interest, such as bots or publishers clicking their own ads. ▶ video
K
L
- Lazy loading ads Lazy loading requests an ad only when its slot gets close to the screen, instead of loading every ad on the page as soon as the page opens. ▶ video
- Line item A line item is a booking in an ad server such as Google Ad Manager that holds what to serve, where, when, at what price and at what priority. ▶ video
- Line item priority Line item priority is the number that decides which Ad Manager line items get first claim on an impression. Lower number, higher priority. ▶ video
M
- Mediation Mediation is the layer in an app that decides which ad network fills each ad, using a waterfall, a bidding auction or a mix of both. ▶ video
- MRC (Media Rating Council) The MRC (Media Rating Council) is a US industry body that audits and accredits media measurement and sets standards such as viewability. ▶ video
N
O
- Open auction The open auction is the programmatic auction any approved buyer can join, bidding in real time for each impression above the publisher's floor. ▶ video
- OWNERDOMAIN OWNERDOMAIN is an ads.txt 1.1 line naming the business domain of the company that owns the site, so buyers can match it to sellers.json. ▶ video
P
- Page RPM Page RPM is ad revenue per 1,000 page views: estimated earnings ÷ page views × 1,000. It shows what your traffic earns. ▶ video
- Passback A passback hands an ad request that one demand source cannot fill to another source, so the slot gets another chance to show a paid ad. ▶ video
- PPID (publisher provided ID) A PPID (publisher provided ID) is your own ID for a reader, sent to Google Ad Manager for frequency capping and audiences. It must be hashed or encrypted. ▶ video
- Prebid Server Prebid Server is open-source software that runs header bidding on a server, so the page or app sends one request instead of calling every bidder.
- Prebid.js Prebid.js is free, open-source JavaScript that runs header bidding auctions in the reader's browser and passes the best bids to the ad server. ▶ video
- Preferred deal A preferred deal gives one buyer first look at impressions at a fixed price, with no volume promised. Passed impressions go to auction. ▶ video
- Price bucket A price bucket is one price step, such as 2.80, that Prebid rounds a bid down to before sending it to the ad server as hb_pb. ▶ video
- Price granularity Price granularity is the size of the price steps Prebid uses when it rounds bids down into price buckets for the ad server. ▶ video
- Price priority line item A Price priority line item is a non-guaranteed Google Ad Manager line item at priority 12 that competes on price. Prebid setups use it. ▶ video
- Pricing rules (unified pricing rules) Pricing rules are Google Ad Manager settings that set floor prices for programmatic demand on matching inventory. They were called unified pricing rules. ▶ video
- Privacy Sandbox Privacy Sandbox was Google's set of Chrome tools meant to replace third-party cookies for ads. Google retired most of it in October 2025. ▶ video
- Private marketplace (PMP) A private marketplace (PMP) is an invite-only auction where selected buyers bid on a publisher's inventory, usually above a higher floor. ▶ video
- Programmatic guaranteed Programmatic guaranteed is a deal where one buyer reserves a fixed volume of impressions at a fixed price, delivered through programmatic pipes. ▶ video
R
- Remnant inventory Remnant inventory is the ad space left after direct-sold campaigns take their share. Most of it is now sold through programmatic auctions. ▶ video
- Revenue per session Revenue per session is total ad revenue divided by sessions: what one visit earns across every page it views. It is often shown per 1,000 sessions. ▶ video
- Rewarded ad A rewarded ad is one the user chooses to watch in return for a reward, such as an extra life or in-game coins, in an app or on the web. ▶ video
S
- Second-price auction In a second-price auction the highest bid wins but pays just above the runner-up's bid, or the floor if that is higher. ▶ video
- Segmented floors Segmented floors set different minimum prices for different slices of inventory, such as country, device, size or time of day, instead of one floor. ▶ video
- sellers.json sellers.json is a public file an SSP or exchange posts to name the company behind each seller account ID that appears in publishers' ads.txt files. ▶ video
- Send all bids Send all bids is Prebid's default mode: it passes every bidder's price to the ad server, not just the top bid, using bidder-specific keys. ▶ video
- Server-side bidding (S2S) Server-side bidding runs the header bidding auction on a server: the page sends one request and the server calls each bidder, instead of the browser. ▶ video
- Sponsorship line item A Sponsorship line item is a guaranteed Google Ad Manager booking for a share of impressions, such as a takeover. It has top priority, 4. ▶ video
- SSAI (server-side ad insertion) SSAI (server-side ad insertion) stitches video ads into the content stream on a server, so the viewer's device plays one continuous stream. ▶ video
- SSP (supply-side platform) An SSP (supply-side platform) is software that sells a publisher's ad impressions to many buyers, usually through real-time auctions. ▶ video
- Sticky ad A sticky ad stays fixed on screen while the reader scrolls, usually at the top or bottom of a phone screen or in a desktop sidebar.
- Supply path optimisation (SPO) Supply path optimisation (SPO) is buyers keeping only their best routes to a publisher's inventory and cutting duplicate, costly or unclear paths. ▶ video
- SupplyChain object (schain) The SupplyChain object (schain) lists, inside the bid request, every seller that handled the impression, so buyers can trace the path to the publisher. ▶ video
T
- TCF string A TCF string, or TC string, encodes a reader's consent choices under IAB Europe's framework and travels with ad requests so each vendor can check it. ▶ video
- Temporary CPM A temporary CPM is the opportunity-cost price Google Ad Manager gives a guaranteed line item so Ad Exchange can compete with it. ▶ video
- Third-party cookie A third-party cookie is set by a domain other than the site the reader is on, such as an ad company's, letting it recognise the same browser across sites. ▶ video
- Trading desk A trading desk is a buy-side team, usually linked to an agency, that runs programmatic buying for advertisers through DSPs. ▶ video
U
V
- Value CPM Value CPM is an estimated CPM you set on a Google Ad Manager line item. Remnant line items use it instead of their rate to compete with AdX. ▶ video
- VAST VAST (Video Ad Serving Template) is the IAB standard XML a video player receives to know which ad to play and which tracking links to call. ▶ video
- Video completion rate Video completion rate (VCR) is the share of video ad impressions that play to the end: completes divided by impressions. ▶ video
- Video quartiles Video quartiles are the tracking events a player fires as an ad plays: at 25% (first quartile), 50% (midpoint) and 75% (third quartile). ▶ video
- Viewability Viewability measures how many ad impressions could actually be seen: viewable impressions as a share of measurable impressions. ▶ video
- Viewable impression A viewable impression is an ad with at least 50% of its pixels on screen for 1 continuous second, or 2 seconds for video. ▶ video
W
- Waterfall A waterfall offers each impression to demand partners one at a time, in a fixed order based on past prices, until one accepts. ▶ video
- Wrapper timeout The wrapper timeout is how long a header bidding wrapper waits for bids before handing the auction to the ad server. Late bids are left out. ▶ video