It was late at night when I was describing to my friend how cooking is such a time consuming chore. He recommended me to purchase an Air Fryer which can seamlessly cook chicken in about 20 minutes. I got excited and looked up prices for an air fryer only to find that they are expensive. As the excitement dropped, I just slept.

The next morning, I wake up to find several air fryer ads on my Facebook feed. Before watching a YouTube video, they show me an air fryer ad. I got spammed with air fryer ads for many days. How do they know that I am looking for an air fryer?

There are many ways websites track your online activity, but one of the oldest and the most common ways of tracking is through cookies. Let’s find out how they work.

How Cookies Work?

Let’s say you visit a website for the first time where the default language is German, but you change the setting to English. The website then sends a document to your web browser with an ID. The next time you visit the website, its identifies the document in your web browser and remembers that you chose the language as English, and hence displays in English. This document with an ID is called a Cookie.

Cookies are documents that store information about your activity in websites. For example, e-commerce websites send cookies to your browser while you add items to your cart. If you close the browser, the items in the cart are stored in the cookie. When you open the browser again, the information from the cookie is retrieved and you still see the items in your cart. Earlier, this kind of session details used to be stored in the website’s server which burdens the server with data from different users. As cookies are stored in your web browser locally, website servers save a lot of space.

As you see, cookies make things convenient for users and servers. Furthermore, websites cannot check cookies that originated from another website. Facebook cannot access cookies in your browser from Amazon or BestBuy. If that’s so, why are cookies accused of invading our privacy?

There are two kinds of cookies in the internet – Primary Cookies and Third-Party Cookies. The types of cookies mentioned in the above examples are primary cookies. These are cookies set by the website that you are directly browsing in. The cookies that track you all over the internet are the notorious third-party cookies described in the following section.

Third-Party Cookies (The Bad Guys)

While primary cookies are set by the websites you are browsing in, third-party cookies are the ones set on your browsers by websites that you are not directly browsing in. So how does this work?

Let’s say you are reading an article in a blog like The Big Brain Blog. As you are reading, notice the social media widgets on your left. This webpage consists of code borrowed from Facebook to display the Facebook widget. Because this widget is actually hosted on Facebook’s server, when you first read an article in this blog, Facebook is able to send a cookie to your web browser.

Social Media Widgets In This Site

After reading this article, let’s say you read a celebrity news article in, which also consists of a Facebook “Share Post” widget. As you enter, Facebook identifies the cookie it placed in your browser from So now Facebook knows you read educational articles at The Big Brain Blog and you are also interested in celebrity news. By making this match, they make a browsing profile of you.

Social Media Widgets In Celebrity Articles
Screenshot from here

Another example of third party cookies usage is Google Ads – the largest online advertisement publisher. Companies pay google to publish ads all over the internet. You must have seen google ads in websites which appear as banners at the top or on the side. If you have seen one of them, your browser is carrying a cookie from google. If you visit other sites which host google ads, google will identify the cookie on your web browser. In this way, google is able to make a unique online profile of you by matching the articles you read, items you purchase, and news that you follow. And based on this profile, they send you targeted ads. Most likely, the third-party cookies tracked that I searched for air fryer prices, so now I am spammed with air fryer ads.

Large companies like Google and Facebook have their presence all over the internet. Think about it, there are Google Ads in almost all websites. There are Google sign-in widgets in all the service sites. With tracker cookies, they know a lot about us than we do about ourselves. Google uses these data mostly for targeted advertisements. As long as they don’t sell the data, our information is supposedly safe.

Unfortunately, Facebook had “unintentionally” leaked its users’ data to Cambridge Analytica – a British political advertising firm – who were tasked with helping Donald Trump in the 2016 US Presidential Elections. The company tried to influence the voting decisions of millions of Americans by profiling users based on the data and sending them targeted political ads.

Google and Facebook are not the only ones with tracker cookies. There are millions of them in the internet. Most of them are used by marketing companies for targeted advertisement, which is not necessarily bad. But there are others who sell our data to data brokers, who profile us based on our activities, and manipulate and control our behaviors. Surely, online privacy is a myth.

Concluding Remarks

I think its too late to do anything significant. These companies have tracked more than enough of our digital footprints. However, if you would like to do some damage control, you can start by disabling trackers in your web browser. You can do that in Firefox and Chrome, while Safari blocks third-party cookies by default.

You can also use browsers that value privacy over profit. For example, I use the browser called Gener8. It disables all trackers and blocks all advertisements. But, there is also an option through which you can earn points to watch personalized ads. With those points, you can purchase various items, gift cards (including Amazon, Spotify, and Netflix), and discounts on services.

Use this link to download Gener8 and get paid to watch ads that you prefer to see.

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