In computing, a cookie (also tracking cookie, browser cookie, and HTTP cookie) is a small piece
of text stored on a user's computer by a web browser. A cookie consists of one or more name-value
pairs containing bits of information such as user preferences, shopping cart contents, the
identifier for a server-based session, or other data used by websites.
It is sent as an HTTP header by a web server to a web browser and then sent back unchanged by the
browser each time it accesses that server. A cookie can be used for authenticating, session tracking
(state maintenance), and remembering specific information about users, such as site preferences or
the contents of their electronic shopping carts. The term "cookie" is derived from "magic cookie", a
well-known concept in UNIX computing which inspired both the idea and the name of browser cookies.
Some alternatives to cookies exist; each has its own uses, advantages, and drawbacks.
An HTTP Cookie is simple pieces of text and not an executable code (like viruses). They are
neither spyware or viruses, although cookies from certain sites are detected by many anti-spyware
products because they can allow users to be tracked when they visit various sites.
Most modern browsers allow users to decide whether to accept cookies, and the time frame to keep
them, but rejecting cookies makes some websites unusable. For example, shopping carts or login
systems implemented using cookies do not work if cookies are disabled.
A message given to a Web browser by a Web server. The browser stores the message in a text file.
The message is then sent back to the server each time the browser requests a page from the server.
The main purpose of cookies is to identify users and possibly prepare customized Web pages for them.
When you enter a Web site using cookies, you may be asked to fill out a form providing such
information as your name and interests. This information is packaged into a cookie and sent to your
Web browser which stores it for later use. The next time you go to the same Web site, your browser
will send the cookie to the Web server. The server can use this information to present you with
custom Web pages.
So, for example, instead of seeing just a generic welcome page you might see a welcome page with
your name on it.