Protecting Your Privacy Online

When you do anything online, you leave a trail. Learn how online tracking works and what you can do about it.

What To Know About Online Tracking


When you visit a website, it might place a file called a cookie on your browser. Websites use cookies to customize your browsing experience. When a website you visit places a cookie on your browser, that’s a first-party cookie. Here are some examples of how websites may use first-party cookies:

  • A news website shows local weather and stories about topics you’re interested in.
  • A website remembers your username or items you left in your shopping cart.

The websites you visit often allow other companies to place cookies as well — for example, to deliver ads targeted to you. These are third-party cookies. Here are some examples of third-party cookies:

  • An advertising company places a cookie and sees that you visited a website about running. It then shows you an ad for running shoes when you visit other sites.
  • An analytics company uses a cookie to get details about your visit to a website — like how much time you spent on the site and the pages you visited. It can use the information it collects to spot problems with the site and make it better.

Other Online Tracking

Companies may track you using methods that are not based on cookies. For example, when you use an app on your smartphone, advertisers may use a unique identifier generated by your smartphone to track you.

Or they may use a technique called device fingerprinting. Device fingerprinting uses your browser’s unique configurations and settings to track your activity.

Companies may also use techniques to connect your identity to the different devices you use to go online — say, your laptop and your smartphone — and then tailor ads to you across all your devices.

What You Can Do About Online Tracking

You can’t completely get rid of targeted ads, but a few steps can help. The steps you take on one device (like your laptop) usually do not carry over to your other devices (like your mobile phone). And if you use more than one browser, the changes you make to one browser don’t affect the others. So remember to check all your devices and browsers.

There’s no global, one-stop solution. Expect to spend some time modifying the settings the first time you do this. After that, follow-up checks should take less time.

Change your browser privacy settings

You can choose to have more privacy when you go online by adjusting the privacy settings on the browsers you use. These settings let you do things like

  • see what cookies are on your computer and delete them
  • decide what type of cookies you want to allow, including tailoring those settings by website
  • turn on private browsing mode

If you clear your cookies instead of blocking them, they’ll be set again when you browse, so you may need to clear them from time to time.

Here’s how to change the privacy and security settings on different browsers:

Make sure to adjust the settings on each device and each browser you use.

Change your smartphone privacy settings

Most mobile devices have privacy settings that let you control whether ads will be targeted to you based on your app usage and browsing activity. These may include

  • Reset advertising identifiers: Under the “advertising” section of your phone’s privacy settings, you may find an option to reset advertising identifiers. If you reset, your device will generate a new identifier. Any data associated with your previous advertising identifier will not be linked to your new identifier. But tracking will start fresh with your new identifier. Keep in mind that this setting relates to tracking while you are using apps. To address privacy when you use a mobile web browser, use the controls in your browser or one of the opt-out tools described below.
  • Tracking control: Apple introduced a setting that requires app developers to ask for permission before they track your activity across apps or websites. As you use an app, you may see a notice asking if you want to allow the app to track your activity. If you decline, the app can’t access your device’s advertising identifier.
  • Location controls: Many companies access your device location to send you ads based on your location. Your device’s location controls let you limit the sharing of your location. You’ll usually find these controls under the “location services” section of your privacy settings.
  • Ad personalization: In the “advertising” section of your privacy settings, there may be a “Personalized Ads” or “Ad Personalization” control. If you turn off personalized ads, your phone will stop using your info to show you targeted ads.

Opt out of targeted advertising

Groups representing members of the advertising industry — the Digital Advertising Alliance and the Network Advertising Initiative — also have free opt-out tools. If you want to opt out, be sure to opt out on each device and browser.

Consider an ad blocker

Ad blockers keep ads from popping up or appearing on your browser. They work by filtering specific content according to rules set by the program or by the user. A wide range of ad blockers is available and you can find them by searching online. Compare features and reviews to decide which ad blocker is best for you.

Ad blockers don’t necessarily block all ads. That’s because some companies’ ad blockers show ads from advertisers that meet certain criteria set by the company. Ad blockers also do not detect or block viruses or malware.

Change your internet-connected TV privacy settings

If you have an internet-connected TV, you may also want to change the settings that let companies track information about what you watch. Many streaming devices and smart TVs have privacy settings that let you control advertising data collection and use. Search online for the name of your television or streaming device and “privacy settings” to get specific guidance on how to adjust these settings. 

Opt out of data broker sites that sell your personal information

Data brokers collect personal information about you from a variety of sources. Then they resell or share that information with others for many purposes, including

  • verifying your identity
  • detecting fraud
  • making decisions about your eligibility for things like credit, employment, insurance, and housing
  • marketing products

Many data brokers are not affected by the privacy settings described above because they aren’t just advertisers.

Start by opting out of offers for credit and insurance at In addition, many data brokers offer opt-outs. For the most part, it’s a one-by-one process. To get information about data brokers, including whether you can opt-out, search this database from the state of Vermont.

Another option is to pay a company to do the work for you. If you decide to hire a company to opt out for you, make sure you know how much it costs and which data brokers they cover, and share only the personal information needed.