Cookies – What are they and what do they do?


When I mention ‘cookies’, you probably imagine an oven-baked treat of the chocolate chip variety. In computer terminology though, cookies are completely different, but they both have something in common – they can sometimes make your life just a little bit better.

So what are cookies? What are they doing on our computer? Are they bad for us? Read this blog to find out.

Did someone say cookies?

If you’ve ever been online or browsed the Internet you’ve probably heard of cookies or clicked ‘accept’ on a pop-up banner to accept them. This unfortunately doesn’t send a batch of chocolate chip cookies to your computer. But it does contain helpful information about you and your preferences.

Web browsers create simple text files called cookies when you visit websites on the Internet. Your device stores the text files locally allowing your browser to access the cookie and pass data back to the original website.

For example, if you visit a website and wanted to select a certain language, you’d select an option that said ‘I’d like to view your website in English’. The website would then save that information to a small document – a cookie – to your computer. The next time you visit the same website, it would be able to read the cookie it saved earlier and ‘remember’ your language preference and display the website in English. This saves you the inconvenience of selecting the language again.

Are there different types of cookies?

Just like the edible ones, there are different types of Internet ones too. Different cookies have different functions and purposes.

Session cookies

Session cookies are commonly used on online stores or shopping websites, such as Amazon or Ebay. They help websites recognise users and the information provided as you move from one web page to another and remember what items you placed in your shopping basket. They only retain information about a user’s activities for as long as they are on the website and are deleted when you close your web browser.

Permanent cookies

Permanent cookies are stored on your computer until it expires or until you manually delete it. Permanent cookies can identify a user by assigning a unique tag to the cookie. These are the types of cookies used on websites that need to know who the user is but offer the ‘Remember me’ function when we enter our name and password. When you select a website to remember you, the website remembers the username and password so you don’t need to re-enter it every time you visit. The result is that it offers faster and more convenient access. In addition to authentication, other website functions are possible such as menu preferences, preferred theme, language selection or even internal site bookmarks.

Third party cookies

Third party cookies are files that have been stored onto your device by a website that is different from the website you are actually visiting. Advertisers use these to track your visits to various websites on which they advertise. These cookies are used to collect information about what sites you visit, things you like, dislike and purchase. They often use this information to show ads, products or services specifically targeted to you.

Are cookies bad?

Sweet treats should only be eaten in moderation.

But on a serious note, Internet cookies are technically harmless. They are simple text files that are stored passively, and cannot be used to view data on your hard disk or capture other information from your computer.

However, websites can use cookies to track users as they browse the web, collecting highly personal information and often transferring or selling that information to other websites without permission or warning. Viruses and malware can also be disguised as cookies and some, such as the zombie cookie, can even be re-created even after they’ve been deleted.

Summing up cookies

Since the beginning of cookies, the popularity of these clever little helpers exploded and they gradually evolved into a more complex, yet essential part of the internet.

At first, cookies would contain just a few preferences such as language. But soon, developers realised that the more information they could store, the better experience they could provide to their users. This development holds the potential for constantly improving browsing and user experiences. At the same time it becomes more difficult to understand what information is being collected, stored and shared.

It’s up to the creators of a website to determine what information they do and don’t store, and more importantly; what they use that information for. Cookies are a tool. Just like a hammer or a saw they can be used for bad things, but they are intended to be used for good things. The responsibility lies with the people using them.

If you’re a business who collects and stores information through cookies, consider creating a Website privacy policy to be compliant with the cookie law.

Alan Cheung

Paralegal at Rocket Lawyer
Alan is a paralegal at Rocket Lawyer UK. He has a law degree from the University of Westminster and has recently graduated from the Legal Practice Course at BPP Law School. He is passionate about employment law and intellectual property and strongly believes in accessible and affordable legal services.
Alan Cheung