Author: Tom Kemp
Published: Jul 02, 2025
Did you ever wonder why, after shopping for red shoes on a website, you started seeing ads for those same shoes following you around on the internet? That’s not a coincidence. It happens because your online activity is being tracked, allowing advertisers to “retarget” you. Retargeting is a way for advertisers to show you ads based on things you’ve looked at before, even after you’ve left a website.
This kind of tracking doesn’t just happen in your web browser. It can also happen through your mobile devices, apps, or even other internet-connected devices. In this blog post, we’ll explain how website tracking works and ways to limit this if you choose.
Ways that Websites Track You Online
Tracking on websites has historically been enabled through the use of cookies. A cookie is a small file that stores user data to identify a specific visitor to a website. “First-party” cookies are tied to a particular website and remember your past activity on that site. For example, a website may recognize if you had an item in your shopping cart the last time you were logged in and show it in your cart the next time you visit.
However, in many cases, businesses also configure their websites to include “third-party cookies.” Third-party cookies are principally used by online advertising networks. These networks provide software code that publishers embed into their websites. Each time you visit a website featuring this code, a third-party cookie is downloaded on your device, tracking your online activity and behavior across other websites. This is why you see targeted ads on the sites you visit that are tied to your past web browsing history.
How to Limit Website Tracking
If you don’t want to see ads based on your online behavior or prefer to limit the ability for businesses to track your website visits, there are several steps you can take.
Delete browsing data
If you don’t want personalized ads based on past website visits, you can delete cookies within your browser and clear your search and browsing history.
Customize your privacy settings
Your browser’s security and privacy settings can provide varying degrees of control over how much of your online activity websites can collect about you. For example, you can block third-party cookie collection and suppress personalized ad delivery based on your online activity. For instructions on how to set these privacy settings and delete cookies on popular web browsers, visit this FTC website.
Review privacy notices and tracker settings
Businesses that must comply with the California Consumer Privacy Act are required to post their privacy policy through a link using the word “privacy” on their homepage and other web pages. The link is usually at the bottom of a business’s website (e.g., “privacy preferences” or “do not sell or share my personal information”). In selecting these options, a cookie pop-up window will typically appear, letting you turn cookies on or off for particular types of website tracking. You can choose the options that match your preferences.
Opt out of audience-matched advertising
Many advertisers use your online activity to show you ads that match your interests. If you prefer not to see personalized ads, some ad industry groups let you opt out of this type of personalized advertising. Visit the FTC’s “Opt out of personal ads” page if you are interested in free tools to help you limit how participating advertisers use your information.
Consider privacy-centric plug-ins or privacy-focused browsers using an ad blocker
Many browsers support third-party extensions or plug-ins that can provide additional privacy controls, such as ad blocking. The CPPA encourages you to consult trusted reviewers who can recommend third-party plug-ins or more privacy-centric browser alternatives to popular browsers. Ad blockers help block trackers, pop ups and unnecessary cookies, making your browsing more private. Read reviews to learn about the features and choose which ad blocker meets your needs.
Additionally, some browsers offer a “private” or “incognito” mode that deletes your browsing history after you close your browser, but these modes will not prevent a business from collecting your activity while on their websites.
Enable an opt-out preference signal on your browser
One simple and easy way to opt-out of the sale and sharing of your personal information is through an opt-out preference signal, or OOPS for short.
An OOPS is a user-friendly and straightforward way for consumers to automatically exercise their right to opt-out of the sale and sharing of their personal information with the businesses they interact with online. An OOPS, such as the Global Privacy Control. can either be a setting on your internet browser or a browser extension. With an OOPS, consumers do not have to submit individual requests to opt-out of sale or sharing with each business.
Stay in Control
Protecting your privacy online does not have to be complicated. The simple changes above can make a big difference. Continue to visit Privacy.ca.gov for more resources to protect your privacy.