How Do Cookies Get on a Computer?

How Cookies Get on a Computer

A Web server sends its cookie to your computer when you browse to a website. If the cookie remains on your computer the next time you visit the website, your computer sends it back to the server to identify you as a previous visitor. If the website displays advertisements from a network such as Google AdSense, you may receive the cookie for that network as well. Because this cookie originates from a website other than the one that you are visiting, it is called a 'third-party cookie.' Neither first-party nor third-party cookies contain personal information; each cookie contains a unique code that identifies your computer.

Benefits of Cookies

A cookie allows you to customize websites according to your preference without affecting the experience of other users. Websites often contain customization options, allowing users to change the language, color scheme, text size and other items. A cookie allows these preferences to be persistent; the next time you visit the website, it remains as you configured it. E-commerce websites also use cookies to make shopping carts persistent; if you browse a shopping website and place an item in your cart, that website's cookie allows the item to remain in your cart if you return to purchase it later.

Drawbacks of Cookies

Advertising networks use cookies to track your browsing habits. For example, the DoubleClick DART cookie used by Google for its AdSense program allows Google to track your Web searches, along with all of your visits to websites that display AdSense ads or take part in the Google Analytics program. Google analyzes this data to determine which advertisements you are most likely to click, and displays those advertisements when you visit websites displaying AdSense ads. The benefit if this is that you are more likely to see advertisements online that interest you. However, some people would rather not share their browsing history -- even if it is anonymous -- with a company that intends to profit from it.

Avoiding Cookies

All Web browsers have privacy features that allow you to customize how they handle cookies. You can configure your browser to accept all cookies, to refuse third-party cookies or to refuse all cookies. This may increase the time needed to do some things online -- such as adjusting your preferences for a website -- but many browsers allow you to enter exceptions for your cookie configuration.