Google Ads: definition, operation and cost models

Google Ads is an advertising platform for planning, managing and optimizing campaigns on Google Search, the Display Network, YouTube and other Google Group environments.

What is Google Ads?

With Google Ads, formerly Google AdWords until 2018, Google provides a central tool for search engine advertising. Over the years, the platform has become the largest online advertising network in the world. It allows businesses to advertise on Google Search, YouTube, and millions of partner web pages.

With Google Ads, advertisers can plan, manage and optimize campaigns for Google Search and then flexibly supplement them with ads on the Google Display Network and YouTube. This makes it possible to drive different marketing objectives, from increasing reach to generating conversions, via a single platform.

Ad Formats in Google Search

Google Ads allows you to display ads directly on Google search results pages (SERPs), but also on platforms like Google Play or Google Shopping. On SERPs, ads typically appear above and below organic results. Google is also extending distribution via partners of the Research Network.

Responsive RSA (Responsive Search Ads) ads are today the standard format on the Search Network. Advertisers enter multiple headlines and descriptions, which Google automatically combines to generate ads tailored to the user’s query, device and context.

The current character limits are as follows:

• Titles: up to 30 characters per title (max. 15 titles possible)
• Descriptions: up to 90 characters per description (max. 4 descriptions possible)
• URL path: up to 15 characters per field (2 fields available)

Ad formats on the Google Display Network

The reach of Google Ads is not limited to the search engine. Indeed, the Google Display Network allows advertisers to place ads on Google services such as Gmail as well as millions of partner sites. Video campaigns, for their part, are broadcast in particular on YouTube. Besides text ads, multimedia ad formats are also available to advertisers.

Instead of static banner formats, today mainly responsive display ads are used. These automatically adapt to different locations, devices and screen sizes.

• Illustrated ads: Banner advertising still relies on standardized formats, but it is distributed and optimized in an automated manner.
• Video ads: Google Ads offers different video ad formats, including In-Stream Ads, In-Feed Video Ads, and video ads in YouTube Shorts. These can be delivered standalone or as a component of modern campaign types.

The objective is to disseminate a advertising as relevant as possible. Google Ads campaigns are certainly still based on keywords, but today also take into account many other signals: user behavior, context, type of device, location or time of the request.

While individual keywords once played a central role, Google Ads now relies heavily on automation and machine learning. Ads are served dynamically to maximize the likelihood of a defined action, such as a purchase, registration or contact request.

Keywords

The principle of Google Ads is simple: display ads that correspond to a concrete search intention and that provide real added value. Keywords are used to associate ads with specific themes and to cover relevant queries. These can be single terms or longer phrases used by potential customers when searching for a product or service.

Today, the success of a campaign no longer relies solely on the manual selection of keywords, but on theinteraction between search intent, automation and conversion data.

In modern campaigns, broad match keywords are often combined with automated bidding strategies. This makes it possible to capture semantically similar queries, even if they do not correspond exactly to the defined keywords.

The Keyword Planner remains useful for evaluating ideas, search volume, and competition. However, for continuous optimization, actual data from queries and conversions is generally more influential than simple predictions.

Ad auctions

Google determines, via a real-time auction, which ad is shown for a given query. With each search, the ad ranking (Ad Rank) is calculated. It decides whether an ad is displayed and at what position on the results page.

The main factors taken into account are:

• The set bid (or automated bidding strategy)
• The quality level (Quality Score)
• The expected impact of extensions and other ad elements
• Contextual and user-related signals, such as device type, location, time, or assumed intent

Quality Score remains an important lever because it reflects the relevance of the ad, keyword and landing page. However, today it is integrated into a highly automated and data-driven overall system, and serves more as a diagnostic indicator.

Costs and billing models

To define the costs of a Google Ads campaign, advertisers have different options bidding and billing models. In practice, automated strategies, oriented towards specific objectives, are increasingly replacing manual auction management.

The main billing models are:

• CPC (cost-per-click): you only pay when a user clicks on the ad. The actual cost per click results from bidding and competition and is often lower than the set maximum bid. This model is common for search campaigns.
• CPM (cost-per-thousand): billing is based on 1,000 impressions. You set the maximum amount you are willing to pay for a thousand views. This model is mainly used for display and video campaigns aimed at awareness.
• CPA (cost-per-acquisition): here, the objective is a concrete action, for example a purchase or a lead. In practice, CPA is generally used as a target value in an automated bidding strategy, not as a fixed price per conversion.

In addition, strategies such as Target CPA or the Target ROAS allow Google to automatically adjust bids to achieve defined goals. The system then analyzes numerous signals in real time, including device, location, time of request or probability of conversion.

To keep spending under control, each campaign relies on a daily budget defined. Ads are served within this budget, which Google can distribute flexibly to optimize performance over time.

In the context of GDPR, the Digital Services Act (DSA) and increasing restrictions on third-party cookies in browsers like Safari or Firefox, tracking in Google Ads has evolved profoundly. Classic measurement based solely on cookies now gives way to hybrid approaches: cookieless tracking, modeled data, consent signals and server-side solutions.

Today, a reliable measure of success relies on a combination of observed data and modeled data. Google Analytics 4 (GA4) constitutes the central standard: based on an event-driven model, it can be linked directly to Google Ads in order to transmit conversions, evaluate campaign performance and automatically optimize bids based on the data collected.

Data protection plays a decisive role, especially within the European Union. To use Google Ads and GA4 with personalized features like remarketing in the European Economic Area (EEA), Google requires the implementation of Consent Mode v2. This mechanism transmits users’ consent choices to Google and allows Google Ads and GA4 to use modeled conversions when users have not given their full consent. The legal basis, however, remains valid consent, collected for example via a cookie banner.

At the same time, the server-side tagging gains importance. By moving part of the data processing to a controlled server environment, companies gain more control over data flows, improve the stability of measurements and can better reconcile marketing performance and GDPR compliance.

Before launching a Google Ads campaign, it is essential to define clear objectives :

• Increase brand awareness
• Increase traffic to the website
• Generate leads
• Generate sales
• Encourage in-store visits

Google Ads offers considerable reach and allows you to reach potential customers at the precise moment they show intent. However, success requires more than just serving ads: it requires a clear strategy, rigorous technical setup, and reliable performance measurement.

By aligning campaigns with specific marketing objectives, intelligently leveraging automated bidding strategies and regularly analyzing performance data, it is possible to use Google Ads effectively and profitably over the long term, while complying with legal data protection requirements.