As the Adtech industry is constantly evolving, Reed Smith brings you a clear and concise dictionary that sets out key definitions and provides an introduction to each term to enhance your understanding of the latest industry jargon. This dictionary is a first of its kind in not just including general definitions but explanations focusing on the legal issues and legislation and covering U.S., Europe and Asia.

This dictionary has been updated as of September 2023.


AdChoices is a self-regulatory program initiated by the Digital Advertising Alliance for online interest based advertisements used mostly in the US and Canada. The AdChoices logo (recognisable as a triangle with an ‘i’ in the middle) is used by participating companies on websites and, when clicked on, gives users information about how their information is used for relevant advertising and opt out options.

Ad Exchange

A digital marketplace where Advertisers and Publishers are able to buy Ad Inventory. It is a real-time auction platform that does not favour the buyer or the seller, it merely acts as a platform to enable the trading of Ad Inventory.

Ad Fraud

A type of complex scam where fraudsters trick Advertisers by pretending to represent online advertisement Impressions, clicks, Conversion or data events to generate revenue. The fraudsters create fake traffic, fake leads or ineffective advertisement placements, which the Advertiser unsuspectingly purchases. There are various different types of Ad Fraud. Some examples include: (i) Pixel stuffing – stuffing one or more illegitimate advertisements into a Pixel to simulate the display of multiple advertisements on a single page to take CPM credit for serving those Impressions even though users are not actually seeing the advertisements; (ii) Domain Spoofing – impersonating a valuable Publisher site and selling “counterfeit” Ad Inventory on Ad Exchanges to Advertisers who believe they Traffic (NHT) – as further described below, an umbrella term for many versions of generating illegitimate or ‘invalid’ traffic intended to generate revenue by simulating live, measurable advertisement traffic.

Ad Inventory

The space for advertising available from the Publisher for sale to an Advertiser. Sometimes the term “media inventory” is used. The space will vary depending on where it appears – for example, on a mobile, website or TV etc., as well as on the type and the size.

Ad Network

A company that connects Advertisers (who want to place advertisements) with Publishers (who wish to host the advertisements). Publishers have the ability to sell and aggregate Ad Inventory from numerous sources in a single buying opportunity. An Ad Network can also help to create targeting capabilities and contains features similar to that of an Ad Exchange.

Addressability or Addressable Marketing

Refers to the ability to use media to target specific individuals, rather than large groups of anonymous third-parties.

Advanced Data Protection Control (ADPC)

A joint project between the Sustainable Computing Lab at the Vienna University of Economics and Business and NOYB for a proposed automated specification for the communication of users’ privacy decisions (particularly pursuant to GDPR and PECR), namely for users to give or refuse Consent, to withdraw Consents previously given, as well as to object to Processing. It provides an alternative to existing non-automated CMPs and functions using the exchange of http(s) headers or an equivalent JavaScript interface.


The brand which is the subject of the advertising.

Advertising Cookies

Cookies used to store or share information with third parties related to a user’s browsing activity to create an advertising profile and place relevant advertising on the website or third party websites.

Age-Appropriate Design Code (AADC)

The UK’s AADC (a statutory code) requires that Profiling – including for Behavioral Advertising – must be switched off by default for children (under 18s), unless a service can demonstrate a compelling reason for the Profiling to be on by default, taking into account a child’s best interests. Any Profiling must ensure that adequate safeguards are in place to prevent harm to the child, such as Consent, meaning children must choose to enable Targeted Advertising to be provided as part of an online service.

Analytic Cookies

Cookies used to analyse a user’s journey on the website to evaluate and improve performance. For example, a Google Analytic cookie is commonly used by companies to track and report website traffic volumes. Analytic Cookies are still caught by the PECR and GDPR regimes but there is some debate as to whether all types of Analytic Cookies are as invasive and when precisely Consent is needed, especially where First Party Analytic Cookies are deployed.

Application Program Interface (API)

An API essentially allows two applications to talk to each other. It connects web- site programs and software systems for the purpose of sharing data. Digital products and services are able to send and receive information through API. Examples would include a social media platform that has APIs to enable users to access the service on other devices or for value added services such as a single sign-on. APIs can be used for a variety of different things. Typically there will be standard terms that apply to the API and developer guidelines for coding and use around them.

Attribution Reporting

The purpose of such reporting is to explain and show the Conversion path of the user – i.e. how or where can that Conversion be attributed to – for example, what advertising Campaign made the user take the action? It may measure a user’s actions on a website from the first time they enter to the time they become a customer.

Audience Overlap

A common issue marketers face when advertising on platforms that build native audiences or lookalikes. Essentially, Audience Overlap occurs where two separate ad campaigns end up directed at the same audience despite trying to target different audiences. Audience overlap leads to increased marketing costs.

[Audience] Suppression

The process of removing specific people or groups from an advertising campaign.

Behavioural Advertising

Advertising targeted to individuals based on observed behavior that has been tracked over time. Depending on applicable law, Consent and notice requirements related to the Processing of related data or the use of Cookies to access and store related data may vary.


A computer program that interacts with a website as if it was a real user. Another computer will see the Bot interaction as if it was from a user, unless that computer has been programmed to detect the Bot.

Brand Safety

A set of measures that work to protect the reputation of a brand from the negative or damaging effects of undesirable or inappropriate content when advertising online. These measures can include employing blocklists or allowlists, preventing ads from being displayed on websites in certain content categories (such as piracy, adult, hate speech, and known malware sites), partnering with third-party verification vendors.


The primary regulated entity under the CCPA, defined as an entity that collects California consumers’ Personal Information, does business in California, and meets a relevant data collection or revenue threshold. The data collection threshold of 50,000 California residents or “consumers” set forth in the CCPA will double to 100,000 when the CPRA takes effect in 2023. Businesses are responsible for honoring consumer rights requests, disclosing how consumer Personal Information is collected, used, and shared, and contractually ensuring the compliance of Service Providers, Contractors, and other partners whom they provide with consumer data.