Glossary#
Essential AdTech terms defined. No jargon in the definitions—just clear explanations.
A#
Ad Exchange Marketplace where advertisers and publishers buy and sell ad inventory in real-time auctions. Think stock exchange, but for ads. Examples: Google Ad Exchange, OpenX, Rubicon Project.
Ad Network Companies that aggregate ad inventory from multiple publishers and sell it to advertisers. The middleman between publishers and advertisers. Examples: Google Display Network, Taboola, Outbrain.
Ad Server Technology that stores, manages, and serves ads to websites or apps. Tracks impressions, clicks, and basic performance. Examples: Google Ad Manager, Sizmek.
Algorithmic Bidding Using machine learning to automatically adjust bids in real-time based on conversion probability. Also called automated bidding or smart bidding.
Attribution The process of determining which ad touchpoints deserve credit for a conversion. Complex because users see multiple ads before converting.
Audience Segmentation Dividing users into groups based on shared characteristics (demographics, behaviors, interests) for targeted advertising.
B#
Bid Request Information sent to advertisers during an RTB auction, including user data, page context, and ad placement details. Advertisers use this to decide whether to bid and how much.
Bid Response Advertiser’s reply to a bid request, containing their bid amount and the creative to show if they win.
Bounce Rate Percentage of users who visit a site and leave without interacting. High bounce rates often indicate poor ad targeting or misleading creatives.
C#
CAC (Customer Acquisition Cost) Total cost to acquire a new customer, including all marketing and sales expenses. Critical metric for determining profitability.
CDP (Customer Data Platform) System that collects and unifies customer data from multiple sources to create a single customer view. More focused on known customers than anonymous users (unlike DMPs).
Click-Through Rate (CTR) Percentage of ad impressions that result in clicks. Formula: (Clicks ÷ Impressions) × 100. A 2% CTR means 2 out of 100 people who saw the ad clicked it.
CMP (Consent Management Platform) Tool that manages user privacy consent, especially for GDPR and CCPA compliance. Handles cookie consent banners and tracks user preferences.
Contextual Targeting Showing ads based on page content rather than user tracking. Making a comeback as cookies disappear. Example: shoe ads on running blogs.
Conversion Desired action taken by a user (purchase, signup, download, etc.). What counts as a conversion varies by campaign goal.
Conversion Rate Percentage of users who complete a desired action. Formula: (Conversions ÷ Visitors) × 100.
Cookie Small text file stored on a user’s device to track behavior across sessions. Third-party cookies (set by domains other than the one you’re visiting) are being phased out.
CPA (Cost Per Acquisition) How much you pay for each conversion. Formula: Total Ad Spend ÷ Conversions.
CPC (Cost Per Click) How much you pay each time someone clicks your ad.
CPM (Cost Per Mille) Cost per thousand impressions (mille = thousand in Latin). Standard pricing model for display advertising. If CPM is $5, you pay $5 for every 1,000 times your ad is shown.
D#
DCO (Dynamic Creative Optimization) Technology that automatically assembles personalized ad creatives in real-time based on user data. Same template, different content for different users.
Demand-Side Platform (DSP) Software used by advertisers to buy ad inventory programmatically across multiple ad exchanges. Examples: Google Display & Video 360, The Trade Desk, Amazon DSP.
DMP (Data Management Platform) System that collects, stores, and activates audience data for advertising. Primarily handles anonymous user data via cookies and device IDs.
Dooh (Digital Out-of-Home) Digital advertising on billboards, transit displays, and other physical locations. Programmatically bought like online ads.
F#
First-Party Cookie Cookie set by the website you’re visiting. Used for login sessions, preferences, shopping carts. Not being deprecated like third-party cookies.
First-Party Data Data you collect directly from your customers (website visits, purchases, email interactions). The most valuable data type as third-party cookies disappear.
Frequency Capping Limiting how many times a user sees the same ad. Prevents ad fatigue and wasted impressions.
G#
GDPR (General Data Protection Regulation) European privacy law that requires explicit user consent for data collection and gives users rights over their data. Applies globally if you serve EU users.
H#
Header Bidding Technology that lets publishers offer inventory to multiple ad exchanges simultaneously before calling their ad server. Increases competition and revenue compared to waterfall approach.
I#
Impression Single instance of an ad being displayed. Counted when the ad is served, though viewability standards vary.
Interstitial Full-screen ad that appears between content pages. Often annoying but effective for mobile apps.
ITP (Intelligent Tracking Prevention) Apple Safari’s cookie-blocking technology that limits third-party tracking. Forces advertisers to adapt to privacy-first browsing.
L#
Lookalike Audience Group of users who share characteristics with your existing customers. Created using machine learning to find similar users for targeting.
LTV (Lifetime Value) Total revenue a customer generates over their entire relationship with your company. Used to determine how much you can afford to spend on acquisition.
M#
Measurement Protocol API that allows sending event data directly to analytics platforms server-side instead of via browser JavaScript. Used in server-side tagging.
O#
Optimization Process of adjusting campaign parameters (bids, targeting, creatives) to improve performance. Can be manual or algorithmic.
P#
Pixel Tiny 1x1 image or JavaScript snippet that tracks user actions. When the pixel loads, it fires tracking data to an analytics or ad platform.
PMP (Private Marketplace) Invitation-only ad exchange where premium publishers sell inventory to selected buyers at negotiated rates. More controlled than open exchanges.
Programmatic Advertising Automated buying and selling of ad inventory using software and algorithms. Includes RTB, PMPs, and programmatic guaranteed deals.
R#
Retargeting Showing ads to users who previously visited your site but didn’t convert. Reminds them to come back and complete the action.
ROAS (Return on Ad Spend) Revenue generated per dollar spent on ads. Formula: Revenue ÷ Ad Spend. A 4:1 ROAS means you earn $4 for every $1 spent.
RTB (Real-Time Bidding) Auction-based system where ad impressions are bought and sold in milliseconds as pages load. Core technology powering programmatic advertising.
S#
Second-Party Data Someone else’s first-party data that they share with you directly. Essentially a partnership where both parties benefit from shared data.
Server-Side Tagging Tracking approach where events are sent to your server first, then forwarded to ad platforms. Bypasses ad blockers and gives you more control than client-side tracking.
SSP (Supply-Side Platform) Software used by publishers to manage and sell their ad inventory programmatically. The sell-side equivalent of a DSP. Examples: Google Ad Manager, Pubmatic, Magnite.
T#
Third-Party Cookie Cookie set by a domain other than the one you’re visiting. Used for cross-site tracking. Being phased out by browsers due to privacy concerns.
Third-Party Data Data purchased from external vendors who aggregate information from multiple sources. Becoming less valuable as cookies disappear.
U#
User Agent String sent by browsers identifying the device, operating system, and browser type. Used for device targeting and detection.
V#
Viewability Measure of whether an ad was actually seen by a user. IAB standard: 50% of pixels visible for at least 1 second (display) or 2 seconds (video).
W#
Waterfall Sequential ad serving approach where inventory is offered to buyers one at a time in priority order. Slower and less efficient than header bidding.
Walled Garden Closed ecosystem where a platform controls user data, inventory, and measurement. Examples: Facebook, Google, Amazon. You can advertise there but don’t own the data.
Z#
Zero-Party Data Information users intentionally share with you (survey responses, preferences, profile details). The most ethically collected data, though harder to obtain than passively tracked data.
This glossary covers core AdTech terminology. For deeper dives on any concept, refer to the relevant chapter in the book.