Glossary

Ad tech terms, explained

The pricing models, ad formats, and metrics referenced across the site, defined in one place.

Pricing models

Bid: The amount an advertiser offers to pay for each unit of traffic, such as per thousand impressions on CPM or per click on CPC.; Example: A $2.00 CPM bid means paying up to $2.00 for every 1,000 impressions.
CPA (Cost Per Action): A pricing model where the advertiser pays only when a specific action completes — an install, a lead, a signup. Highest cost per unit, lowest risk to the advertiser.; Example: Paying $4 for each completed app install.
CPC (Cost Per Click): A pricing model where the advertiser pays per click, regardless of what happens after. A middle ground between CPM and CPA on both cost and risk.; Example: Paying $0.05 each time a visitor clicks the ad.
CPM (Cost Per Mille): A pricing model where the advertiser pays per thousand impressions, regardless of clicks or conversions. Lowest cost per unit, most useful for testing a new offer or GEO.; Example: A $1.50 CPM means paying $1.50 for every 1,000 impressions served.
Floor Price: The lowest price a publisher or network will accept for a unit of traffic. A bid below the floor is not eligible to win the impression.; Example: With a $1.50 CPM floor, a $1.00 CPM bid can't win that traffic.

Metrics

Conversion Rate (CR): The percentage of clicks (or visitors) that complete the advertiser's goal action, such as an install or a signup. Conversions divided by clicks, times 100.; Example: 50 installs from 1,000 clicks is a 5% conversion rate.
CTR (Click-Through Rate): The percentage of impressions that result in a click — a core signal for how well a creative and ad format fit the traffic they're shown to.; Example: 20 clicks from 1,000 impressions is a 2% CTR.
eCPM (Effective CPM): A publisher-side metric: total ad revenue divided by total impressions, multiplied by 1,000. Used to compare earnings across ad formats and pricing models on a common basis, even when the underlying traffic was sold on CPC or CPA.; Example: $30 earned from 20,000 impressions is a $1.50 eCPM.
Fill Rate: The percentage of ad requests from a publisher's zone that were actually filled with an ad, rather than returning nothing.; Example: If a zone makes 1,000 ad requests and 900 return an ad, its fill rate is 90%.
Impression: One instance of an ad being displayed to a visitor, whether or not it's clicked. The basic unit CPM pricing is billed on.; Example: A page that loads an ad once counts as one impression, even if nobody clicks it.
ROI (Return on Investment): Profit as a percentage of what was spent: revenue minus cost, divided by cost, times 100. The number most advertisers use to decide whether to scale a campaign.; Example: Spending $100 on a campaign that earns $130 in revenue is a 30% ROI.

Ad formats

In-Page Push: An ad format that renders a native-style notification directly in page content, rather than through the browser's permission-gated push system — no opt-in step required from the visitor.; Example: A small notification card that slides into the corner of an article while someone reads it.
Interstitial: A full-screen ad format that fires at a natural transition point — between pages, after an action, or on session start — rather than sharing the screen with other content.; Example: A full-screen promo shown when a visitor moves from one page of a site to the next.
Page Bar: A non-intrusive on-page toolbar ad format that runs alongside a site's content without occupying dedicated ad space.; Example: A slim chat-style bubble anchored to the side of the page, showing a new-message alert.
Popunder: An ad format that opens a new window behind the visitor's active page, so it's seen once they finish their current session rather than interrupting it.; Example: A visitor clicks a link, and the ad opens in a window behind the page they are reading.

Platform and traffic

Ad Network: A platform that sits between advertisers who want to buy traffic and publishers who want to sell it, matching campaigns to ad zones and handling delivery, pricing, and payouts.; Example: An advertiser funds a campaign and a publisher adds a zone; the network matches the two and settles payment.
Ad Zone: A publisher's designated slot for serving ads — created in one of the network's supported formats, then reviewed and approved before it starts serving live traffic.; Example: A publisher adds a Popunder zone for their blog, then pastes the generated code snippet into the site.
ads.txt: A public text file at the root of a publisher's domain that lists which companies are authorized to sell that site's ad inventory, so buyers can check the inventory is legitimate.; Example: A line such as example-network.com, pub-1234, DIRECT authorizes that account to sell the site's ads.
CC Submit: A conversion flow in which the visitor submits credit-card details, usually for a trial or a purchase. It is a complex flow, so it is typically tested on CPM first.; Example: A free-trial signup counts as a CC submit once the visitor sends the card form.
click2sms: A conversion flow in which tapping a button opens the phone's messaging app with a pre-filled text to a short number; sending it completes the subscription.; Example: Tapping “Join” opens a text addressed to a short code — sending it finishes the flow.
Conversion Flow: The sequence of steps a visitor takes from clicking an ad to completing the advertiser's goal — anything from a one-tap install to a multi-field signup form. Flow complexity is a major factor in choosing a pricing model.; Example: Ad click, landing page, email entry, confirmation: four steps, so more complex than a one-tap install.
Frequency Cap: A limit on how many times the same visitor is shown the same ad within a set period.; Example: A cap of 3 per day means one visitor sees a given ad at most three times in 24 hours.
GEO: Shorthand for the geographic location (country or region) traffic originates from — a primary targeting dimension for advertisers and a major factor in the payout rates publishers see.; Example: Targeting US, CA and GB shows a campaign only to visitors in those countries.
Invalid Traffic (IVT): Impressions or clicks that don't come from real, interested people — bots, scripts, or accidental and forced clicks. Networks review traffic for it so that advertisers aren't billed for it and publishers aren't paid for it.; Example: A script that loads a page thousands of times to inflate impressions is invalid traffic.
OpenRTB: The IAB Tech Lab's open standard for how an ad slot and a bid are described in real-time bidding, so a seller's ad request and a buyer's bid response can be read by different systems.; Example: A bid request says the slot is a 300×250 banner on a mobile page in Canada; the reply carries a price and the ad markup.
PIN Submit: A conversion flow, common in carrier-billing offers, where the visitor enters a one-time PIN received by SMS to confirm a subscription.; Example: After entering their phone number, the visitor types the 4-digit code they were texted.
Postback (S2S Tracking): A server-to-server notification: when a conversion happens, the advertiser's tracker or server sends a request to the ad network to report it, so the conversion is credited to the right campaign without relying on the visitor's browser.; Example: When someone installs your app, your tracker calls a postback URL with the click ID so the install is attributed.
RTB (Real-Time Bidding): An auction that runs in a fraction of a second while a page loads: the ad slot is offered to several buyers at once and the highest eligible bid wins that impression.; Example: Three buyers bid $1.20, $1.50 and $1.35 CPM for the same slot; the $1.50 bid wins and its ad is shown.
Self-Serve: A platform you operate yourself — creating an account, adding funds, launching campaigns or ad zones, and reading reports — without going through a sales rep or account manager.; Example: On a self-serve network you pick a format, a pricing model and your targeting, then submit the campaign for review.
sellers.json: A public JSON file that an ad platform publishes at the root of its domain, listing the publishers and intermediaries it sells inventory for, so buyers can check who they are paying. It works together with ads.txt.; Example: A buyer matches the seller ID on a site's ads.txt line against the platform's sellers.json to see whether that seller is the publisher or a reseller.
Traffic Source: Where visitors come from — a publisher's website, an app, a social channel. In advertising it also describes the inventory a campaign buys.; Example: A news site and a URL shortener are two different traffic sources.
Vertical: The category of offer or industry an advertiser promotes, such as iGaming, VPN and utility software, eCommerce, sweepstakes, or dating.; Example: A promotion for a VPN app belongs to the VPN and utility vertical.
Whitelist / Blacklist: Lists of sources (sites, zones, categories) that are explicitly allowed (whitelist) or blocked (blacklist) from a campaign or ad zone.; Example: Blacklisting a poorly converting site stops a campaign buying traffic from it.