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What are cookies?

May 13, 2022

What are cookies?

Cookies are small files sent to your browser from websites you visit. These files track and monitor the sites you visit and the items you click on these pages. 

Retailers use cookies to remember what the apparel and shoes you've clicked on, the items you've stored in your online shopping cart, and the products you've purchased in the past. News sites use them to remember the stories you've opened in the past. Some sites might use cookies to remember your password and username so that they fill in automatically when you visit the site’s login page.

This might seem intrusive, and it's true that many users resent cookies following their activities across the internet. But companies and advertisers say cookies improve your online experience.

An example? A news site you visit each day can use the information it has collected through cookies to recommend other stories you might want to read. A retailer might use the information compiled through its cookies to suggest products you might like to buy based on the handbags, laptops, and smartphones you've clicked on its and other retailers' sites.

Meet the computer cookie

A computer “cookie” is more formally known as an HTTP cookie, a web cookie, an internet cookie, or a browser cookie. The name is a shorter version of “magic cookie,” which is a term for a packet of data that a computer receives and then sends back without changing or altering it.

No matter what it is called, a computer cookie is made up of information. When you visit a website, the website sends the cookie to your computer. Your computer stores it in a file located inside your web browser. (To help you find it, this file is often called “Cookies.”)

What do browser cookies do?

The purpose of the computer cookie is to help the website keep track of your visits and activity. This isn’t always a bad thing. For example, many online retailers use cookies to keep track of the items in a user’s shopping cart as they explore the site. Without cookies, your shopping cart would reset to zero every time you clicked a new link on the site, making it difficult to buy anything online.

A website might also use cookies to keep a record of your most recent visit or to record your login information. Many people find this useful so that they don’t have to continually type in their passwords and login information at sites they visit frequently.

Different types of cookies track different activities. Session cookies are used only when a person is actively navigating a website; once you leave the site, the session cookie disappears. Tracking cookies may be used to create long-term records of multiple visits to the same site. 

Authentication cookies track whether a user is logged in, and if so, under what name.

Are internet cookies safe?

Under normal circumstances, cookies cannot transfer viruses or malware to your computer. Because the data in a cookie doesn’t change when it travels back and forth, it has no way to affect how your computer runs.

However, scammers are clever. Some might disguise viruses and malware as seemingly harmless cookies.

There are also certain types of cookies created by legitimate companies and internet service providers (ISP)that concern privacy advocates. A “zombie cookie,” for example, is a cookie that recreates itself after being deleted, making them difficult to manage. Third-party tracking cookies can erode your online privacy, because they make it easier for parties you can’t identify to watch what sites you are visiting, what files you are downloading, and what images you are clicking on.

Then there are "supercookies." These are a type of tracking cookie that ISPs insert into an HTTP header. ISPs use these cookies to collect information about users' browsing activity and history. Some privacy advocates oppose supercookies, pointing out that most users will never know that a supercookie is tracking their online activity.

Should you enable or disable third-party cookies?

When you visit any website, it will store at least one cookie — a first-party cookie — on your browser. This cookie remembers your basic activity on the site and doesn't track your information when you visit other sites.

Many sites, though, store third-party cookies on your browser, too. These cookies allow social media companies, advertisers, and other website operators to track your browsing and online activity at other sites. If you want to boost your online privacy, it makes sense to block these third-party cookies.

It takes different steps to disable third-party cookies depending on what browser you are using.

Microsoft Edge : To disable third-party cookies on the Microsoft Edge browser, click the gear icon in the upper right-hand corner. Select “Settings” in the new menu that opens. Click “View Advanced Settings.” In this menu, find the “Cookies” heading. Select “Block only third-party cookies.”

Chrome : Click the three lines in the upper right-hand corner of the browser. Next, click “Settings.” In this menu, click “Show advanced settings.” Click on the “Privacy” heading and then click “Content settings …” In this menu, you can check the box next to “Block third-party cookies and site data" to stop third-party cookies from tracking your online activity.

Firefox: Click on the three lines in the Firefox browser’s top right-hand corner. In the "Options" menu, choose "Privacy & Security." On the right-hand side of the page, you’ll then see Firefox's "Content Blocking" choices. Check the circle next to the "Custom" option. Next, select the checkbox "Cookies." You can then choose "All third-party cookies" in the drop-down list to disable these tracking programs.

Banning all browser cookies could make some websites difficult to navigate. You also might not get the best experience on some sites. If you disable third-party cookies, your city might not pop up when you log onto a weather site. Retailers won’t be able to target their products more closely to your preferences, either. 

Many users, though, would happily trade these downsides for an increase in their online privacy. You’ll have to determine on your own what you value most.

Frequently asked questions

What are cookies? 

Cookies are small files sent to your browser from websites you visit. These files then track and monitor the sites you visit and the items you click on these pages. 

How are cookies used? 

Cookies remember the products you’ve clicked on, the locations you’ve checked frequently, types of stories you are interested in, and even your login information. They create a personalized internet experience to streamline your searches. 

What are third-party tracking cookies? 

These cookies are used most often by social media sites, companies, and marketers to track your online activity when you are visiting sites other than their own. They can then recommend products they think you’d like when you return to their site. 

What are primary cookies?  

When you visit any website, it will store at least one cookie — a first-party cookie — on your browser. This
cookie remembers your basic activity on the site and doesn't track your information when you visit other sites. 

Are cookies harmful? 

For the most part, cookies aren’t harmful. They usually don’t transfer viruses or malware to your devices. 

What about privacy and cookies? 

Privacy advocates do have concerns with cookies, most notably with third-party cookies, which track your online activity, something that will erode your privacy when scouring the web. 

Should you disable cookies? 

Browsers do give you the option to disable or enable cookies. If you are concerned about privacy and want to keep retailers, marketers, and social media sites from tracking your online activity, it makes sense to disable third-party cookies on any browser you are using.

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