Ad privacy in Google Chrome is designed to show relevant ads while limiting how much personal data is shared with advertisers.
Chrome uses a system called the Privacy Sandbox, which replaces traditional third-party tracking methods. Instead of allowing websites to track you across the web using third-party cookies, Chrome processes much of your browsing activity locally on your device.
One key feature is ad topics. Chrome identifies general categories of your interests, such as travel or sports, based on your recent browsing history. These topics are stored on your device and shared selectively with websites to help display relevant ads, without revealing your full browsing history.
Another feature is site-suggested ads, where websites can show ads based on your activity within that site, rather than tracking you across multiple sites.
Chrome also limits or blocks third-party cookies, which are commonly used for cross-site tracking. This reduces the ability of advertisers to follow your activity across different websites.
Chrome’s ads privacy features improve your privacy online. At the same time, they support ads and the no charge content and services that ads make possible.
Sites that you visit can embed content from other sites to enrich their content, like images, ads and text. This embedded content can use third-party cookies to track you as you browse the web. You can choose to block third-party cookies; however, this may cause some website functionality to break. For example, embedded content like videos, social media feeds and ads might not display correctly. The ad privacy features in Chrome can deliver the same browsing experience without the tracking.
When used for advertising, ad privacy APIs protect your identity and minimise the amount of data that sites can use to learn about you. Here’s how:
- Protect your identity: The ad privacy APIs limit a site’s ability to track your activity as you browse. The APIs also protect you against re-identification. For example, based on your activity and other information that a tracker already has, like your identity on a website, a tracker could guess who you are.
- The Topics API provides sites with a high-level sense of your interests based on your recent browsing history. Instead of essentially unlimited information, the new API only allows sites to receive up to three interests, such as 'Sports'. It also occasionally returns a random interest. We call this 'adding noise' and we do it to protect your identity. All of this means that the Topics API makes it much harder for a tracker to gather enough information to identify you. Learn more about the Topics API.
- The Protected Audience API allows sites to store only limited browsing history on your device. Ad tech companies can only process your cross-site data on your device. This makes it much harder to identify you and to gather information about you. Learn more about the Protected Audience API.
- The Attribution Reporting API helps advertisers measure the effectiveness of their online ads without needing to track your activity across sites and apps. Like Topics, this API also adds noise to obscure unique characteristics that could be used to identify you. And it adds time delays to reports, which also makes it much harder to connect your activity across sets of data. These safeguards prevent many re-identification attacks that are possible today with user identifiers, even if those identifiers are obscured and encrypted. Learn more about the Attribution Reporting API.
- Minimise data collection: Today, ad tech companies can collect large amounts of your data as you browse the web because of technologies like third-party cookies. The ad privacy APIs limit the amount of data that can be learned about you at any given time, particularly as you browse from one site to another, significantly improving your privacy when third-party cookies are blocked. The APIs make it much harder for an ad company to identify you, which means that it’s harder to build and associate a profile with you. The APIs also establish other data limitations, such as:
- The Topics API limits advertisers to collecting just a small number of topics per week based on your recent browsing history. Today, third-party cookies and other identifiers allow ad tech companies to collect highly detailed information about you based on nearly all of your browsing history over time.
- The Protected Audience API restricts who receives data and what data they receive when you see a personalised ad. With this API, only companies actually involved in showing an ad on a web page receive information about that ad impression. By contrast, today, when a personalised ad is placed on a page using third-party cookies, a wide range of companies can gather information, even if they didn’t have anything to do with showing the ad.
- The Attribution Reporting API limits the amount of information that can be connected with you for any given ad shown. And for aggregate reports, pooling many user reports into a single report to protect your identity, the API effectively limits the types of information that can be measured and also caps the amount of conversion information recorded. Today, trackers can collect an unlimited amount of data, including detailed information about your activity.
- Greater accountability from ad tech providers: Keeping track of ad tech companies that use these APIs for ads provides new visibility and accountability. Chrome uses an 'attestation' model, which requires ad tech companies to clearly and publicly commit to using the limited data that they receive in a proper, privacy-preserving manner. Learn more about greater accountability from ad tech providers.
- More robust user controls: Today, managing your ad privacy with third-party cookies requires effort. Either you can turn third-party cookies off completely, at the cost of losing non-ad-based uses of third-party cookies, like persistent sign-in services, or you can keep third-party cookies active and sort through hundreds of cookie domains and often unrecognisable ad tech providers. With the new APIs, it’s much simpler to manage your online ad privacy. For example, when personalised ads are delivered via Protected Audience API, you can block topics and sites that you don’t want used to show you personalised ads.
Important: Ads shown by websites are also subject to the site’s policies.
As you browse, these settings allow you to influence the information sites used to show you personalised ads when those sites are using the ad privacy APIs. You can turn off these features in your Chrome settings at any time. You can also delete, allow and manage cookies in Chrome.
To change your Chrome ad privacy settings:
Computer
- On your computer, open Chrome.
- At the top right, select More
Settings.
- Select Privacy and security
- Select the ad feature that you’d like to turn on or off.
Android
- On your Android device, open Chrome
.
- Tap More
- Tap Privacy and security
- Select the ad feature that you’d like to turn on or off.
iOS
Ad privacy settings aren't available for Chrome on iOS devices.
Related resources
You have control over these settings. In Chrome, go to Settings > Privacy and security > Ad privacy. From there, you can view, edit, or turn off features like ad topics and other privacy controls.
Additionally, Chrome does not share personally identifiable information such as your name or email with advertisers through these features.
In summary, Chrome’s ad privacy approach focuses on keeping your data on your device, reducing cross-site tracking, and giving you control over how your browsing activity is used for advertising.
