Ahh, cookies. One of my pet peeves is the amount of bad cookie code I see out there—like the code responsible for the reaction I get from a Web site when I choose not to permit cookies (usually because I'm feeling rebellious). Cookies are one of many ways to turn stateless HTTP into a series of session-based transactions with states like "logged in" and "logged out." Other ways to achieve a similar transformation of HTTP include using authentication, mangling the URLs, and hiding data.
Cookies are the object of my ire because so many Internet programmers assume that "one user equals one Web browser." After all, that's the basic model of the cookie itself. But that assumption is also demonstrably untrue. For example, right now I have three browsers open. And, I've been known to enter an Internet café from time to time and use the browsers it supplies. The problem is that when I move from browser to browser, my cookies don't follow me.
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