What is a cookie?
A cookie is a piece of text that a web server stores on a user's hard disk. They allow a web site to store information on a user's machine and later retrieve it. The information is stored as a name-value pair. A name-value pair is just a named piece of data. It cannot do anything. A website retrieves the information that it has placed on your machine.
How does a cookie work?
Basically, cookie data is the mane-value pairs stored on your hard disk. A website stores the data and later takes it back. Websites cannot look at any other cookie or take any other information from the machine. This is how it works. When you type a Website URL into the browser, the browser sends a request to the website for the page. When the browser does this, it looks on the machine for a cookie file for that website. If it finds a cookie file, the browser sends all of the name-calue pairs to the server. If it doesnt find a cookie, then it doesnt send any data. You can set an option in your browser so that it informs you everytime a site sends name-value pairs. They can be accepted or denied.
How do websites use cookies?
-To determine how many people actually visit the site
They can also see how many visitors arrive, how many are new vs. repeat visitors, and how often a visitor visits.
-To store user perferences
-Shopping sites can use shopping carts and quick checkout options
Problems with Cookies:
-People often share machines. If you use an online store, the store will leave a cookie on teh machine and someone could try to buy something under your account.
-Cookies get erased
-People use more than one machine in a day.
Privacy Issues:
-When you buy something from a catologue, the company has your name and address, and knowledge of the items purchased. This information can then be sold to telemarketers. On a website, everything you do is tracked down. This makes the information sold to telemarketers a lot more precise. Each site has its own policy.
-Cross-site profiling: when a company, such as DoubleClick, puts small GIF files on a site that load cookies onto your machine. DoubleClick can then track your movement across multiple sites, including things you type in search engines. Profiles are then formed with all the information collected.
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