Every time you visit a website, a small pop-up may ask you to accept or reject cookies. Most people click “accept all” to make it disappear, but what exactly are they agreeing to? Ultimately, computer cookies are small pieces of data that websites store in your browser to remember information about you and your activity.
Whenever you click a link or open a new tab, your browser sends a new request to the server. The cookies help websites remember who you are between requests, and help websites recognize that these requests belong to the same visitor. For example, when you log into an online store and add something to your shopping cart, a cookie can help the website remember your session if you start browsing on different tabs. Without cookies or similar technologies, you might have to log in repeatedly or rebuild your cart every time you navigate elsewhere.
There are several types of cookies. Session cookies are temporary and generally disappear when you close your browser. They help websites maintain a continuous session while you navigate across tabs. Persistent cookies remain on your device for a specified period and allow websites to remember your preferences. First-party cookies are created by the website you are on, while third-party cookies are set by other services embedded in that website.
Advertising companies may use third-party cookies to recognize the same browser across multiple websites, helping them build profiles of user’s interests. For example, if you look at a pair of shoes online, you may start to notice advertisements for similar products on other websites. This practice, known as behavioral advertising, can make advertisements more relevant, but it also raises concerns about privacy.
Cookies are not inherently dangerous as they cannot execute programs or infect your computer with viruses. However, they do contain identifiers that allow websites to recognize you, and poorly secured cookies create security risks. In worse case scenarios, if someone obtained a session cookie, they may be able to impersonate a logged-in user in certain circumstances. Websites must therefore protect cookies carefully, particularly those associated with sensitive accounts. Users should be cautious about websites they visit and consider installing protective software programs.