Microsofts definition of a cookie is "A very small text file placed on your hard drive by a Web Page server. It is essentially your identification card, and cannot be executed as code or deliver viruses. It is uniquely yours and can only be read by the server that gave it to you."

They claim that a cookie helps you by saving your time when you register for products or services or for remembering things. What they don't mention is that cookies can be a serious security and privacy concern and CAN be accessed by other servers.
A current vulnerability exists in IE 5.5 and 6.0 (Earlier editions _may_ be effected by it) Which allows a malicious website with a malformed URL to read the contents of a user's cookie which could contain passwords or other sensitive information. This could lead to stealing or altering data from Web accounts, including credit card numbers, and usernames and passwords..

Yet the unpatched version of 6.0 is still available for download at ...