What is a browser cookie?

Browser Cookies

An HTTP cookie is a packet of information sent by a server to a World Wide Web browser and then sent back by the browser each time it accesses that server. HTTP cookies are used for user authentication, user tracking, and maintaining user-specific information such as site preferences and electronic shopping carts.

Cookies have been of concern for Internet privacy, since they can be used for tracking the browsing of a user. As a result, they have been subject to legislation in various countries such as the United States, as well as the European Union. Cookies have also been criticized because the identification of users they provide is not always accurate and because they can be used for network attacks. Some alternatives to cookies exist, but have their own drawbacks.

On the other hand, cookies have been subject to a number of misconceptions, mostly based on the erroneous notion that they are computer programs. In fact, cookies are simple pieces of data unable to perform any operation by themselves. In particular, they are neither spyware nor viruses, despite the detection of cookies from certain sites by many anti-spyware products.

Most modern browsers allow users to decide whether to accept cookies, but rejection makes some Web sites unusable. For example, shopping baskets implemented using cookies do not work if cookies are rejected.

More on cookies...

• A cookie is a piece of data that can be stored in a browser's cache. If you visit a web site and then revisit it, the cookie data can be used to identify you as a return visitor. It remembers the visited pages in your system each and every time by holding data for a single web session, that is, until you close the browser data.
• A cookie is a bit of electronic information that can be placed on your computer when you visit a Web site to track what you look at there, recognize you when you return, and in some cases, track where else you go on the Internet. You can set your online preferences to prohibit, limit, or let you know about "cookies" that a Web site places on your computer.
• Most cookies are not bad things - you may get the impression that cookies are spying devices ("track what you view") - but for the most part they are harmless and quite useful; for example, a cookie might store your login information for a website or a forum, allowing you to visit that website/forum without logging in again each time. This is all the WikiAnswers cookie does.

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First answer by anonymous. Last edit by Jayrusalem. Contributor trust: 574 [recommend contributor]. Question popularity: 606 [recommend question]

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