How Do Websites Use Cookies

Screenshot of browser cookies

Anyone who has navigated the web for any amount of time has probably asked himself, how do websites use cookies? The best way to answer that question is to find out first what cookies are and what they are not.

Web Cookie Definition

Website, or browser, cookies are small text files that web servers create and store on a computer's hard disk. Website cookies are not viruses, programs; executable files, spam, or plug-ins. Cookies are not dangerous to your computer and cannot gain access to your hard drive. The main purpose of these cookies is to store, track, and transmit information that is useful to the website and to the user.

Web Cookie Origins

The term "cookie" derives from "magic cookie" which is defined as a block of unchanged data that is sent out by a program and then sent back to the original source. In 1994, Lou Montulli, an employee of Netscape Communications, decided that cookies would be useful in communications across the web and Netscape released the first cookie supported browser in October of that same year. Internet Explorer integrated cookie support into version two of its browser in 1995.

Why and How Do Websites Use Cookies?

Used correctly, website cookies are important tools for web designers who use them for a variety of reasons ranging from user navigation for Internet shopping to the collection and storage of demographic information. With a few exceptions, website cookies also make surfing the web easier for you, the user.

Internet Shopping

E-commerce websites that implement shopping carts often use cookies. The cookies collect and store data, sometimes across more than one visit, so that when a user places an item in the shopping cart, it will still be there on his next visit. If the user deletes the cookie before he returns, he will have to start over because the website will no longer have access to the information that was originally stored in the cookie.

User Personalization

One of main uses for web cookies is user personalization. For example, cookies store login information like usernames and passwords so that it's easier to log in by way of a form auto-fill the next time a user enters the website. Another personalized use is user preferences. If a user fills in a form about her site preferences, cookies allow the website to remember those preferences, which means the site will deliver information that is relevant to that user each time she visits the website.

Tracking Cookies

Tracking cookies are often the subject of controversy because many people believe they invade individual privacy. Most of the time, in-site tracking is used to assemble usage statistics. For example, web designers and webmasters want to see which pages their visitors are browsing as well as which pages their visitors may avoid. The data that's collected benefits the designer in terms of only supplying relevant information to visitors, and it benefits the users in terms of only receiving relevant and valuable information from the websites they visit.

Third-Party Cookies

Sometimes, third parties set cookies to collect data about browsing habits. Third-party cookies are cookies set by one location but read by another location. This usually occurs when a website (the one you are visiting) collaborates with a third-party website for serving advertising information to Internet browsers. Third-party cookies are the most controversial of all cookie use. Most modern browsers such as Mozilla Firefox, Internet Explorer, and Opera provide users with options to block third-party cookies.

Detailed Cookie Information

If you need more information about browser cookies, the websites listed below can help. A little research can show you how to find and remove suspicious cookies from your hard disk or prevent them from ever being set.

  • Cookie Central gives you everything you ever wanted to know about website cookies.
  • Thief Ware busts myths about the dangers of web cookies while answering commonly asked questions.
  • Mozilla Firefox's support site provides instructions for disabling third-party cookies.
  • Internet Explorer 8's privacy statement has a section on disabling cookies.

Armed with the right information, you'll know how to answer the next time someone asks, "How do websites use cookies?"

How Do Websites Use Cookies