What are cookies?
Everyone is familiar with cookies in the ‘real’ world – they are tasty snacks!
And I’m sure you’ve heard about cookies on the internet, but you are probably wondering what they are, and why they are used.
What are cookies on the internet?
Cookies on the internet are small text files that are stored by your browser when you visit a website. Useful cookies:
- let you log into a site, like a ‘digital’ key.
- remember your preferences for that website.
- let you store multiple items in a digital shopping basket.
The number of cookies set by BBC Recipes
What data do cookies contain?
Cookies may contain different types of information, but they will always include
- the name of the server (website) that set the cookie.
- the lifetime of the cookie (how long it is allowed to be stored for).
- a table with key/data pairs, for example username/cookiemonster, or preferred-website-color/blue.
Cookies can only be read by the website that set them.
Tip: You can easily see what data a cookie stores with a simple browser extension.
What types of cookies are there?
Session cookies: These are temporary cookies that are deleted when you close your browser. These are typically used to let you log into sites, or for shopping baskets that aren’t saved between your shopping sprees.
Permanent cookies: These cookies have a lifespan set by the website, and can be set as first or third-party cookies. They save information so that when you return to the site, your preferences and a unique ID in the cookie tells how frequent you visit the site, and create a digital profile of your preferences. They are often used to target and personalise advertisements to you across the web. When you enable the checkbox ‘remember this’ when you log in, you will set a permanent cookie.
First-party cookies: These are cookies that are set by the site that you are actually visiting. Login cookies are usually first-party, but also language settings and other preferences can be set in a cookie.
Third-party cookies: These are set by third-party services, not the site you are actually visiting. Many social media buttons, or analytics scripts will set third-party cookies so they can track which websites you visit, to better target you with advertisements. They are also commonly known as tracking cookies.
Companies you don’t know about are placing cookies on your computer (a typical list of third-party cookies)
What is cross-site tracking?
Cross-site tracking is a technique typically used by advertising and social networks.
If a web shop or news-media allow third party cookies on their website they allow cross-site tracking. One of the most known examples are cookies from Google – since it’s easy for website owners to add Google cookies to their website and use it to collect usages statistics, a lot of website owners has done it, in fact Google places cookies on about 70% of the most known websites.
Cross-site tracking is then what Google, Facebook and other services do when you visit multiple sites. Imagine you visit a web-shop, a news-website, a recipes-site etc. then Google is allowed to follow you around the web.
This happens because all the websites owners allowed Google to place a cookie in your browser. In a standard browser it is default to allow cross-site tracking, but you can protect yourself by disabling it in your browser.
Are all cookies bad?
No! In fact, many websites would not work without cookies – you wouldn’t be able to log into online banking or shop online without cookies.
The only cookies you should try to avoid if you are concerned about your privacy are third-party (permanent) cookies. These are the privacy-invading cookies that follow you as you browse the web to build a profile of your interests and behaviour.