When you surf the internet, does it surprise you when you see an Ad pop up related to your interest or what you have been searching for lately on the web? That’s because you are being constantly tracked. That’s right my friend, your every move is being noted.
When one uses the internet, they leave back a record of all the websites they visited. Websites use your user accounts, hardware configuration, embed invisible objects and even save a small piece of the data to get hold of your browsing history.
This practice of websites of identifying and collecting user information is known as web tracking. This practice is carried out by website owners to target advertisements, know the site analytics and personalize user experience.
There are a number of ways a user can be identified and tracked. Some of the methods are as follows:
Cookies and Scripts
Cookies are small text files which are stored in your browser. They have numerous uses like remembering your login details when you sign in, remember the items you have added in the shopping cart while shopping in an online store, etc. Cookies also store all settings on a website when it is changed.
When it comes to tracking, cookies can identify and track a user’s browsing activity on a website. This is done to enhance the user experience. But there are also third-party cookies, that track you across multiple websites.
Many websites across the internet use these third-party cookies and scripts for targeted advertisements. Targeted scripts are mostly used by social media websites, for example, those Facebook Like buttons you see on webpages pages store your login details in a cookie to identify you.
IP Address is the easiest way of identifying a person on the internet. Today we connect our mobile phones, laptop and all other electronic devices in hour home to the same network, thus they might all share the same IP address. Using this IP one can roughly track the geographical location of the user.
Spam emails and Ads often use this scheme by posting fake lottery news and so mentioning your location. An IP address does give away your location but not to a very precise level. Also since IP addresses can change or be used by multiple users, it is not very accurate in tracking one user.
When the user clicks on a link on one website and is redirected to another, the other website can see where they came from. For example, while using Facebook, if you click on a link that leads you to another website, that website can see the address of facebook where you came from.
The information sent is contained in the HTTP referrer header. It can also be sent to the advertisers of the ads or tracking scripts placed on the website you were viewing.
HTTP Referrers are used by Web bugs, those tiny one-by-one pixel images that are almost invisible to the naked eye, to track you. This can also be used to track emails user opened if the email client loads images.
Browser fingerprinting is a method that websites use to collect information about your browser type, version, operating system, active plugins, timezone, language, screen resolution and various other settings that are active on your browser.
This is similar to matching fingerprints of humans. Websites bulk-collect a large set of data of visitors in order to later use it to match against browser fingerprints of known users. This isn't very accurate and does not tell who you are. However, it's good for advertising purposes.
The Electronic Frontier Foundation’s Panopticlick website can be used to know more about how many people have the same browser configuration as you and how much data is conveyed from the fingerprint of your browser.
Supercookies like evercookie are stored in multiple places, unlike browser cookies that can be cleared. Supercookie store cookie data in Silverlight storage, flash cookies, browser cookies, browser history, local storage, etc.
Another method used to track user is the unique color assigned to the website when the user visits them. This way the color value of the pixels is a unique identifier of the user.
These were some of the many methods websites use to track users. Hope this gave you a better understanding of why Ads follow you and the different ways your activities are tracked online.