Whats a cookie in the web?
In: Technology
When you visit a website, it stores a little data file on your computer. That’s the cookie. It might be used to record what you looked for last time, for example, or other info about who you are and what you did, which it can use later on — even if you go away and come back later, unless you’ve cleared your cookies.
Ok I replied with this:
“A list of what you’ve done on a site” and it was removed as being in breach of the rules by the automod.
So I guess I need to provide more, but honestly if my 4 year old niece asked that’s exactly what I would say to her.
When you go to a website and do anything, the website sends a summary of what you have done back to your computer to be stored. It’s called a cookie and it’s a list of what you have done.
Websites can arbitrarily decide how in depth it goes, so for example if you spent 10 minutes on an article about dogs and 10 seconds on an article about cats it could record that in the cookie.
The next time you go to that website, your computer sends the cookie back to the website so the website knows who you are and what you did the last time you were there.
In the above example, the website would know you spent more time reading about dogs so could show you more articles on dogs than cats.
Cookies are often used to target advertising accurately, and to save login details.
Basically… cookies are a list of what you’ve done on a site!
Eli5: Imagine you are at a store where all the goods are kept behind a black wall. There is a shopkeeper behind that wall, but you can’t see them and they can’t see you.
Let’s say you need to run out to your car to get your wallet, but you’ve already picked out a bunch of items. You want to tell the shop keeper to keep these items safe for you, but they don’t know what you look like. So the shop keeper writes on a little piece of paper some secret information that would be very hard to randomly copy and a list of the items that you had.
When you return, you show the shop keeper with ticket the shop keeper gave you, and the shop keeper recognizes you and gives you all the items back to keep looking around the store. When you leave, the shopkeeper says they are running a rewards program and gives you a piece of paper before you leave that uniquely identifies you so that the shop keeper can look you up next time you come in and make sure you get all the benefits. You leave the store, but you keep the piece of paper to present the next time you are shopping there.
Imagine now that these papers can automatically add new information to themselves, “client picked up a vacuum cleaner and marveled at it, but did not buy”. “Customer waited for 1 minute at the till before canceling purchase”. Furthermore, you don’t even need to ask for them from the shopkeeper, and you dont need to show them to the shopkeeper, this behavior happens automatically when you leave and enter a store. Every store will say “do you consent to use papers”, if you continue then they will do it without asking again.
When it returns this information to the shopkeeper as you leave, the shopkeeper thinks, hmm this person wants to buy a vacuum, but they did not purchase one. Imagine now that this shopkeeper has many different stores, some are for entertainment or other purposes, but all maintained somehow by the same shopkeeper. You come to one of their establishments and they automatically collect your papers. Suddenly one of the advertisements that was on the wall changes from dog food to a vacuum cleaner, the exact model you were looking at.
You are your computer, the shops are the websites that you interact with, the shopkeeper is the server you are talking to, and the pieces of paper are the cookies.
Less ELI5: Originally they were designed as a way to authenticate users to maintain sessions (a fancy word for not completely resetting all the content of a web page when you leave and come back, things like shopping carts) and maintain bits of information.
The thing to remember is that both the client side code (web page you interact with) and server code is written by the same people. So whereas in our example, the shop keeper had to give you the paper, and you had to choose to return the paper, this behavior is automated by the seller, and the seller doesn’t have to tell you what they are maintaining about your visit. The only authorization you have when you enter a store is “do you want to receive papers that remember you and enhance your experience?” (do you want to enable cookies?)
Nowadays these cookies maintain MUCH more information than people may like, but they can only collect information from you that
A) the browser will give freely or
B) interactions with their site
This is why it is important to check what information your browser freely shares. You can modify this to keep a stronger privacy and ensure the only thing sellers are taking from you are interactions with their website.
Edit: note that one of the features of private mode or incognito mode is limited cookies. Some maintain the cookies until you close the browser, some will not save them at all. But they never use existing cookies. Browse around on some of your favorite sites in private mode and interact a bit. Leave the sites (maybe close the window and reopen in private) and come back and notice how many quality of life features disappear. The sad part is that most sites are hardly functional without cookies. Simply disabling them isn’t really an option for most users.
The term “mark” comes from a time when carnival workers would use chalk to mark the shoulders or backs of gullible guests. This would let other carnival workers know there was an “easy mark” ripe for the picking.
An internet cookie is similar – it’s a market that follows you around from site to site, letting vendors know your interests and habits.
When you visit a web page your browser will send requests to the web server for the different documents needed to display the page. One weakness of this initial system was that there were no way to add persistent features to any web pages. There was no way for the web server to guarantee that the second request came from the same browser as the first one. So if you added things to your shopping cart or even just submitting your login credentials there were no way for the web server to keep that information as you clicked another link. So they came up with the idea that the web server could send a little piece of information to the response and ask your web browser to include that cookie in all subsequent requests. This was a way for the web site to add persistent information to a browser session.
The issues with this is when web sites wants to gather information about what other web sites you visit. The way they do this is to add other web sites to include content from their servers, typically a “like” or “share” button, advertisements or even invisible content. In return they will get better statistics about their users and sometimes monetary compensation. As your browser now sends requests to the servers of the big web site it will include the cookie it received the last time which makes it possible for the web site to see which web sites you are visiting and therefore gather information about almost everything you do online.
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A web cookie is a piece of data that a website stores on your PC. This is often times used to authenticate you when you go to a website that you logged into (Sort of an “ID card”), it can also be used to store website settings.
IE: You visit a website and it asks you if you want to partake in a survey, you click “No” and the website stores a cookie on your PC to indicate that you declined the survey. Next time you visit that website it will not ask you to partake in the survey.
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