User tracking via cookies

karthik · updated · flag

Let’s say you own a pet. A cute little 🐶 called snuffles. If your next-door supermarket owners know about this particular piece of information, they’d obviously try to sell you items like dog food, kennels, and pup vet offers. That’s how valuable the little information “Sally owns a dog!” is.

And knowing more about you will give a store owner a competitive edge!

Now imagine the same thing on the internet. The world wide web has these online supermarkets too! A lot of them! And the internet also has ad companies that would take money from supermarket companies in exchange to display advertisements to people like you.

So obviously, this information “Sally has a dog!” is very valuable to big ad companies like Google and Facebook too. So who would they know this information?

Well, Google and Facebook not only offers ads! They also offer free tools and services like the Google Analytics or the Facebook like button. So if you happen to visit a news website or your friend’s cryptic blog, one way or the other, you’d find some of these free tools installed in them.

For example, let’s say you go read an article on ‘How to groom your pet dog?’ on a site that has a facebook like button and running google analytics in the background. And there it is! Google can now easily grab your information by setting a cookie on your browser. This is that tracking cookie we are talking about.

Now, this is just the beginning!

When you later log in to Google or Facebook, they set a new cookie at that time as well. But behind the scenes, back at their dungeons (literally), their servers compare your new cookie with all the tracking cookies they’ve set. Once they find a relevant match, they link it with your account as ‘The user ‘sally’ who just logged in is the same user who had read an article on pet dog grooming’.

And there you have it!

With this newfound information, these ad companies will start showing you ads for pet dog grooming services everywhere you go on the web while stealthily collection more data on you. In the next lesson, you’ll understand how this practice violates your online privacy and how you can protect yourself from online tracking.