How do websites track us?

Q. How do websites track us?

Answer :-

(a) IP Address :-
IP address is a unique address of your device when you connect to the Internet. It's likely that your computer shares your IP address with the other networked devices in your house or office. From your IP address, a website can determine your rough geographical location.

(b) Cookies and Tracking Scripts :-
Cookies are small pieces of information websites can store in your browser. They have plenty of legitimate uses - for example, when you sign into your online-banking website, a cookie remembers your login information. When you change a setting on a website, a cookie stores that setting so it can persist across page loads and sessions e.g., you change the zoom percentage of your webpage, then this setting will reflect on all opened webpages - because this was stored in a cookie. Cookies can also identify you and track your browsing activity across a website.

Cookies can be :-
(i) First party cookies. These are the cookies that store your own login id, passwords, auto fill information etc. for some websites that you frequently visit.
(ii) Third party cookies. These are the cookies that websites store to know about your search history and web browsing history so as to place advertisements as per your interests.
Third party cookies may result in many unwanted advertisements on your webpages.

(c) HTTP Referrer :-
When you click a link, your browser loads the web page linked to it and tells the website where you came from.
For example, if you clicked a link to an outside website on a webpage then the linked website will get opened and internally information about you such as your IP address, location, your web browser, machine type etc. will also be provided to the linked website - it is known as the HTTP referrer.

(d) Super Cookies :-
Super cookies are also cookies but these are persistent cookies, i.e., they come back even after you delete them. Super cookies (like ever cookie) store cookie data in multiple places - for example, in Flash cookies, Silver-light storage, your browsing history, and HTML 5 local storage etc.
When a website notices that you've deleted part of the super cookie, the information is repopulated from the other location. For example, you might clear your browser cookies and not your Flash cookies, so the website will copy the value of the Flash cookies to your browser cookies.

(e) User Agent :-
Your browser also sends a user agent every time you connect to a website. This tells websites your browser and operating system, providing another piece of data that can be stored and used to target ads.