Not sure what you know about website cookies but that cookie is not an entire history of everywhere you have been on the net.
A cookie's contents are determined by the specific website that created that cookie. Contents vary from site to site. As a general rule, cookies contain random alphanumeric text characters.
Cookies are intended to help you access a site faster and more efficiently. For example, cookies can store information to help you enter a site without having to login. In effect, cookies tell the website that your browser has been to the site before. It does not need to know your exact identity.
When created, cookies normally don't contain any personal information. They don't scan your computer or do any kind of investigation to find out your personal information. Any personal information they might contain is a result of your own input on a website's form. Most of the time, when a cookie does store personal information, this information is coded in such a way that it is unreadable to any third party who happens to access your cookie folder. The only computer that can read and decode the information is the server that created the cookie in the first place.
In addition to encrypting any information stored in cookies, some websites add extra layers of security to browsers' cookie handling processes: store only anonymous but unique content on local cookies; or store personal information on the website's server and make it accessible only by matching with it the anonymous cookie stored on your computer.
This depends on how a website has set up its cookie feature, but generally the content of a cookie is a randomly generated set of characters. For most purposes a website sending a cookie does not need to know who you are - it just needs to remember that it has seen your browser before.
Some websites do write personal information about you into a cookie, but this is only possible if you have provided them with the information in the first place. If personal information is stored in a cookie it is usually encrypted - coded - so that any third party who has access to the cookie folder of your browser cannot read it.
Some website servers use a combination of methods: on your browser they may create a cookie with unique but anonymous content; or on the server side they may create a file that logs that unique but anonymous content alongside any personal information that you have provided.
What can't cookies do?
Cookies are plain text files. They are not compiled so they cannot execute functions or make copies of themselves. They cannot browse through or scan your computer or otherwise snoop on you or dig for private information on your hard disk.
Cookies have a very limited function: to help your browser deliver the full features designed into many of today's websites. These features include smooth login, preference settings, themes, shopping carts, and many other features. Cookies cannot scan or retrieve your personal information.
Because cookies are just harmless files, or keys, they cannot look into your computer and find out information about you, your family, or read any material kept on your hard-drive. Cookies simply unlock a computer's memory and allow a website to recognise users when they return to a site by opening doors to different content or services. It is technically impossible for cookies to read personal information.