Glossary · 36 terms

Ad tech words, in plain English

The terms that come up in every conversation about ad revenue, explained the way we'd explain them to a friend. Missing one? Tell us.

A

Ad exchange

A marketplace where advertisers (through their buying tools) bid to show ads in publishers' ad space, one impression at a time.

Ad refresh

Loading a new ad in the same slot after some time. Done properly, only while the ad is visible and the reader is active, and declared to Google.

Ad request

The call a page makes to ask for an ad for one slot. Not every request becomes an impression: some go unfilled.

Ad unit

A named ad space on your pages, such as "in_article_1". Reports are broken down by ad unit so you can see which spaces earn.

ads.txt

A public text file on your domain (yoursite.com/ads.txt) listing every company allowed to sell your ad space. Buyers check it, and missing lines mean lost demand.

Anchor ad

A banner pinned to the top or bottom edge of a mobile screen while the reader scrolls. The reader can close it.

app-ads.txt

The same idea as ads.txt, for mobile apps. It lives on the developer website listed in the app store.

B

Bid shading

When buyers bid less than an impression is worth to them, because in a first-price auction they pay exactly what they bid. Floors are the counterweight.

C

Core Web Vitals

Google's three measures of page experience: how fast the main content appears, how quickly the page responds, and how much it jumps around.

CPM

Cost per mille: the price for 1,000 ad impressions. A $2 CPM means $2 for every 1,000 impressions.

Cumulative Layout Shift(CLS)

A Google page-speed measure of how much content jumps around while a page loads. Ads that load without reserved space make it worse.

D

Demand

The advertisers and buying platforms that want to buy your ad space. More competing demand usually means better prices.

E

eCPM

Effective CPM: what you actually earned per 1,000 impressions, after everything. Earnings ÷ impressions × 1,000.

F

Fill rate

The share of ad requests that got a paid ad. A floor set too high lowers fill; one set too low lowers price.

First-price auction

An auction where the winner pays exactly what they bid. Google Ad Manager has used first-price auctions since 2019.

Floor price

The lowest price you'll accept for an impression. Bids below the floor lose, even if nobody else bids.

G

Google Ad Exchange(AdX)

Google's ad exchange, where Google's largest advertisers buy ad space. Publishers usually reach it through a partner using MCM.

Google Ad Manager(GAM)

Google's ad server for publishers. It decides which ad fills each ad slot, choosing between Google's demand, Prebid bids and direct deals.

H

Header bidding

Asking several ad exchanges for a price at the same time, before the ad server picks an ad, so they compete directly with Google's demand.

Holdout(Control group)

A small, random share of visits that keeps the old setup. Comparing it with everyone else shows what a change really did.

I

Impression

One ad shown once. It's what most display ads are priced on.

Interstitial

A full-screen ad shown between two pages. Google's own web interstitial has built-in frequency limits.

Invalid traffic(IVT)

Visits or clicks that don't come from genuine interested people, such as bots or paid clicks. Google doesn't pay for it and may withhold earnings.

L

Lift

How much a change improved a result, measured against a control group rather than against last month.

M

Made for advertising(MFA)

Sites built mainly to show ads, often with bought traffic and thin content. Many buyers avoid them.

MCM(Multiple Customer Management)

Google's program that lets an Ad Manager partner manage ad space on sites it doesn't own. It's how most publishers reach AdX.

O

Open Bidding

Google's server-side unified auction for third-party exchanges inside Google Ad Manager. The exchanges bid in Google's auction without any extra code on your page, which is simpler than header bidding but shows you less about each bid.

P

PMP(Private marketplace)

An invite-only programmatic auction at negotiated terms. You choose which buyers can take part and what the price is, and they bid through their normal buying tools.

Prebid

The open-source tool most publishers use for header bidding. Each exchange connects to it through an adapter.

R

Rewarded ad

An ad the reader chooses to watch in exchange for something, like unlocking an article. The reward is given when the ad finishes.

RPM(Revenue per mille)

Earnings per 1,000 pageviews (not impressions). It's the best single number for comparing how well pages earn.

S

sellers.json

A public file where an ad company lists the publishers it sells for. Together with ads.txt, it lets buyers check who is selling what.

SSP(Supply-side platform)

Software publishers use to sell their ad space to many buyers. In practice the words exchange and SSP are often used for the same thing.

T

TCF(Transparency and Consent Framework)

The industry standard for passing a reader's privacy choices (consent) to ad companies, mainly in Europe. GPP is the newer, wider version.

U

Unified Pricing Rule(UPR)

Google Ad Manager's way of applying one price floor across every demand channel at once: AdX, Open Bidding and header bidding bids all have to clear the same floor.

V

Viewability

Whether an ad could actually be seen. The usual standard: at least half the ad on screen for at least one second (two for video).

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