What Are Cookies, What Do They Do, And Are They Harmful?

Cookies, you’ve probably heard the term and you might have some concerns about what they do, but maybe they’re just one of those “techie mysteries.”

By the end of this lesson, you will understand and be able to explain

  • What cookies are
  • How cookies work
  • How cookies help web browsers improve your experience,
  • Why websites and ad-serving companies use cookies
  • How to control which cookies get sent to you

Have you ever wondered how websites remember your username and password every time you visit, or how online stores know which items you’ve added to your shopping cart or how ads seem to know what you’ve been looking for? (kind of creepy!)

Well, cookies make this all possible. Cookies help websites and advertisers customize your online experience.

So what is a cookie?
A cookie is a small digital file that a website places on your web browsers (like Microsoft Edge, Google Chrome or Mozilla Firefox) so the website can identify you when you visit. It doesn’t identify you by name or by personal information, it just assigns your web browser a digital ID that might look something like this.

HTTP/1.0 200 OK
Set-Cookie: lu=Rg3vHJZnehYLjVg7qi3bZjzg; Expires=Tue, 15 Jan 2013 21:47:38 GMT; Path=/; Domain=.example.com; HttpOnly
Set-Cookie: made_write_conn=1295214458; Path=/; Domain=.example.com
Set-Cookie: reg_fb_gate=deleted; Expires=Thu, 01 Jan 1970 00:00:01 GMT; Path=/; Domain=.example.com; HttpOnly

The term “cookie” was coined by web browser programmer Lou Montulli. It was derived from the term “magic cookie”, which is a packet of data a program receives and sends back unchanged, used by Unix programmers.

Here’s How They Work
When you visit a site like google.com for the first time, Google places a cookie on your browser and the next time you visit Google, your browser automatically sends Google.com that same cookie with an ID number that allows Google to recognize you. Not by name…but as a user, using your web browser…you’re just a digital ID

All search engines and most websites use cookies. Cookies allow the sites you visit to recognize your computer when you return and then tailor your online experience accordingly.

It’s a lot like the claim check you get from the dry cleaners. When you come back for your clothes the clerk uses the number on your claim check to give you the right item. In the same way, when your cookie tells Google that you’ve visited its site before, Google is able to remember your preferences — like the fact that you want to see your search results in English or that you’ve turned on the Safe Search (a tool that blocks adult content from your search results).

What else do cookies do?

  • On weather sites they remember which cities you want the forecast for
  • On e-commerce sites they make sure all your selections are in your virtual shopping cart when you go to checkout and
  • On finance sites they allow you to easily track your stock portfolio without having to re-enter the information every time you visit

So you can see that cookies can you a lot of time and, you don’t need to be afraid of them. Like a claim check, a cookie ID is usually just a combination of letters and numbers. Most of the time there’s no personally identifiable information in a cookie file and cookies cannot be used to run programs on your computer, access information on your hard drive or deliver viruses.

There are different types of cookies

first-party cookie is the kind of cookie I just told you about – a cookie that goes back and forth between your browser and the website you’re visiting allowing that website to store information about your preferences.

There are third-party cookies that work a bit differently Unlike first-party cookies that travel back and forth between your browser and the website you’re visiting, third party cookies typically travel between your browser and the website of a company that’s displaying an ad on the site you’re visiting. That’s why they’re called third-party cookies –
because the websites sending cookies to your browser (the ad serving company) is a different site from the website you’re visiting.

Ad serving companies use third-party cookies to remember what ads have already appeared on your browser, that you clicked on an ad for a product and you saw the same ad twice. (For example, you clicked on an ad for Toyota and you clicked on an ad for Camry  twice.)

This information helps advertisers

  • deliver ads that are relevant to your interests
  • control the number of times you see a given ad
  • measure the effectiveness of ad campaigns.

What if you don’t want websites recording your preferences or ad serving companies knowing your web browsing history?

It’s easy to set up your browser to notify you when cookies are being sent, to refuse cookies from certain websites and ad-serving companies or to refuse cookies altogether.

However, bear in mind that, if you disable cookies, websites won’t be able to retrieve your preferences, or save settings to customize your visits in the future.

Nowadays, many websites show a notification that warns you that the website is using cookies and you have to click “Allow” That’s because European law requires that all websites targeting European Union members acquire “informed consent” from users before storing non-essential cookies on their devices.

So now you know

  • What cookies are
  • How cookies work
  • How cookies help web browsers improve your experience,
  • Why websites and ad-serving companies use cookies
  • How to control which cookies get sent to you

Has this information been helpful?  Has it changed the way you feel about cookies?  Please comment below and let me know what you think.

And if you have benefitted, please share this with your friends so they can “make peace with cookies” and have more fun too.

Above all else, Enjoy!


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