Without cookies, the internet wouldn’t be as convenient as we know it. These small files remember your settings, make logging in easier, and tailor content, but they also raise questions about privacy and security.
What are cookies and how do they work?
Cookies, also known as HTTP cookies, are small text files that a website stores on a user’s device. On your next visit, they load automatically and help the site recognize the visitor, save their settings, or make using the website more pleasant. Imagine walking into your favorite café and the barista already knows exactly what coffee you’ll have without you saying a word. That’s how cookies work on the internet—small digital notes websites keep to save you time and improve your experience next time you visit. Thanks to them, sites remember your login details, language preferences, and shopping cart contents, so you don’t have to enter everything again.
They also help website operators track how visitors move around the site, what interests them, and what could be improved. Without cookies, the internet would be a less convenient place—sites wouldn’t recognize you, ads would be entirely random, and logging in would turn into endlessly retyping passwords. Although cookies make the web significantly easier to use, their use also sparks discussion about personal data protection and user tracking.
Invisible risks
While cookies are not dangerous to your device on their own, their ability to track your online behavior can pose a privacy concern. Even though they may seem like a useful tool for personalization, they allow websites to gather information about which pages you visit, what you view, or what catches your attention. All of this can then be used to show you precisely the content and ads that might appeal to you. In this case, however, we lose a piece of privacy because our online steps are increasingly monitored. Cookies can also contain more sensitive information, such as identifiers like your email address.
This process can be unsettling for some users because their online activities are linked to specific personal data. If this doesn’t suit you, modern browsers let you block cookies or delete them regularly. Be aware, though, that you lose certain benefits by doing so, such as faster page loading, personalization, or convenient login.
How cookies communicate with your browser
When you visit a website, a small exchange begins between your browser and the server. The server sends the page and a cookie, a small text bundle of information. This file is carefully designed to remember certain details about you. A cookie contains a name for identification, a domain, a path, flags, a value for storing data, and an expiry date. All of this is saved to your disk, so the next time you return to the same site, your cookies are ready to interact correctly.
Cookies by origin
On the internet, you’ll encounter different types of cookies that recognize you in different ways. Some are like friends who remember what you viewed and what you like, while others follow you across different sites so you keep seeing personalized ads. First-party cookies are the most loyal—these files come directly from the domain you’re currently visiting.
Then there are third-party cookies, which live in a slightly grayer area. They come from entirely different domains and can track you across different sites. Systems like Google or Seznam use them to measure traffic and personalize ads, which can be great for targeted advertising, but it also means your online behavior can be mapped in several places.
And finally, supercookies—they are true masters of precision. They are stored on top-level domains and have access to all subdomains beneath them. This allows them to collect a huge amount of data. Precisely because of this, supercookies are blocked to protect you from excessive tracking.
Cookies by lifespan
Session cookies remember you only during your visit. Once you close the browser window, all traces they left disappear—like your shopping cart when you leave a store. Persistent cookies, on the other hand, are like a membership card that follows you for a long time. When you return to the site, the cookies remember your past actions as if you were a regular.
Special cookies
Cookies aren’t just about personalization and tracking—sometimes they are used for much more sophisticated purposes. Secure cookies are strictly tied to the HTTPS protocol, meaning they can only be sent in a secure environment, protecting your sensitive data from malicious interception attempts. Then there are HttpOnly cookies, which are strictly confidential. Even if scripts appear on the page and try to read them, they have no chance—they are accessible only to the server and do not expose the user on the client side.
And for those who want to see how inventive technology can be, along come evercookies, or „zombie cookies“, which don’t just disappear. When you delete them, some version of them survives elsewhere in your browser.
How long do cookies live?
Even though cookies have set expiration dates, their real lifespan also depends on how users treat them. Some cookies disappear automatically on their scheduled date, others are unlucky and get deleted sooner by users. It’s not easy to measure how often people actually choose to remove cookies. Two older studies from the United States looked into this, but the situation has changed since then, and what it looks like in Europe today remains somewhat unclear.
Laws and cookies
Data protection has become a priority in the digital world, which has brought the unobtrusive yet omnipresent cookies into the spotlight. Their original purpose was purely practical—to enable, for example, saved logins or user settings. Regulation has focused mainly on their darker side, namely cross-site tracking.
The European Union first introduced the so-called cookie law, which required user consent for storing cookies, leading to the widespread proliferation of ever-present banners. It later became apparent that the regulation meant to protect privacy was more of an annoyance to users and reduced website efficiency. The ePrivacy Regulation is now expected to unify rules across the EU and likely tighten requirements for active consent. This may mean the end of pre-checked boxes and further complications for website operators.
Browsers take matters into their own hands
While lawmakers drag out debates over regulations, web browser developers have long been rewriting the rules of the game. Privacy has become a key topic, and tech companies realized that waiting for legislation would mean losing control over how the internet works. Apple sparked a revolution when Safari began gradually blocking third-party cookies in 2017. Firefox didn’t lag behind and, in 2019, launched Enhanced Tracking Protection, significantly complicating life for ad networks and analytics tools.
Then came Google, the biggest player in digital advertising, which initially criticized stricter rules and warned about market impacts. But once it became clear that change was inevitable, it announced its own plan to eliminate third-party cookies in Chrome. Although it presented itself as a defender of user privacy, in reality it strengthened its position. While smaller players lose access to valuable data, Google, thanks to its dominance in search and the advertising ecosystem, remains virtually unthreatened.
Smart data storage in the post-cookie era
As cookies started landing on browsers’ blacklists, web developers had to look for new ways to store data. LocalStorage and sessionStorage are modern solutions that allow information to be kept directly in the browser without constant server transfers. LocalStorage is like a digital safe—data remains stored even after you close the window. SessionStorage, on the other hand, works more like a single-use notepad—everything a site saves there is erased when you close the browser.
Compared to cookies, these technologies have several key advantages. They provide more storage space, don’t affect page loading speed, and are simpler and safer to manage. They are great for storing user preferences, personalizing content, or working offline. They do have limits, though: because they operate only in the browser, they are not ideal for analytics or tracking users across sites. Still, they offer an elegant way to keep important information exactly where it is needed while giving users greater control over their privacy.
Advertising in a world without cookies
How do you target ads when a user’s digital trail fades into the mist? Ad systems long relied on third-party cookies. They tracked users’ steps across sites and served ads aligned with their behavior. Now the game is changing. The removal of these cookies means traditional remarketing stops working, personalized ads lose power, and ad ecosystems must adapt to new rules.
One possible direction is unified sign-in. In the Czech Republic, Seznam is pushing to link its services under one account to track users at least within its own ecosystem. Then there are players like Yahoo who are trying to rebuild ad infrastructure to work on first-party cookies.
Conclusion
Cookies are like the internet’s digital memory—they make life easier, but they can also quietly track us. They’re indispensable for convenient browsing, yet it’s wise to know how to handle them. Whether to let them work for you or limit them for privacy is up to you. The internet without cookies would be less comfortable, but it would leave more room for anonymity.
Frequently asked questions
Can cookies harm my device?
Not by themselves, because they don’t contain malicious code. However, they can collect data about your behavior online, which some consider an invasion of privacy.
How can I manage cookies?
Most browsers let you block or delete cookies, or choose which types to allow. Just look in the privacy settings.
Can the internet work without cookies?
Technically, the internet can work without cookies, but most websites would be much less efficient. Without cookies, websites couldn’t offer a personalized experience or relevant ads.
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