What comes to mind when someone says cookies? No, I am not talking about your mother’s freshly baked chocolate chip cookies. I am talking about Internet cookies. Cookies are one of the most common file types Internet users interact with every day, but the average user really has no understanding of what these little files do. They actually do a lot, yet are designed to not be noticed, at least not directly.
So, what are cookies?
Cookies are files used to record a small amount of data specific to a client’s website. These files reside on a user’s hard drive and are often accessed by a web server or the client’s computer. These tiny files have a few functions, some of which include delivering customized information or results to a user. Cookies are essentially a tiny look-up table made up of pairs of data and key values. Once the cookie has been read by the server or a user’s computer, the resulting data is then retrievable and can be used to present a web page that is unique or has unique characteristics back to the user.
There are essentially two main types of cookies, persistent cookies and temporary cookies.
Persistent cookies stay on your computer’s hard drive even after you have closed your browser. They can also be read by the original website that created them on returning visits.
Temporary cookies are cookies that are stored during your present browsing session. These cookies disappear from your computer once you end your browser session. Cookies can be configured to track different types of data. They can identify and analyze first time and returning visitors, track on page actions, and determine the sequence of pages visited by a user.
Examples of the first-party cookies:
_utma: (Visitor Identifier) Identifies unique visitors. Assigns Visitors a Unique ID upon visiting a website. Expires after 2 years.
Last: 2 years (unless deleted)
_utmb: (Session Identifier) Generates info about a visitor’s session. It sets or updates a session every time a page of a website is visited. It expires after 30 minutes of inactivity.
_utmc: (Session Identifier) Works in conjunction with _utmb. Lasts until the user quits their browser.
_utmz: (Campaign Values )Determines what brought a user to a website. (Ex. referring links, ads, organic search etc.) It also tracks how a user navigates through your page. Expires after 6 months unless otherwise updated.
_utmv: (Visitor Segmentation) Groups visitors into segments. Example members vs. non-members. Expires after 2 years
Privacy and the future of cookies
In theory a cookie is only available to a single site; however, advertisers have started using more sophisticated methods to get around these limitations. Such methods include directing cookies through a single domain and its related servers. This information is then collected and shared across other properties. This is one of the methods used for re-targeted display ads. You visit one website, then some time later you visit another, and low and behold, you are seeing advertising related to the website you visited previously. Did you think that just happened by chance?
Recently some online properties have adopted the use of zombie cookies. Zombie cookies (aka super cookies, flash cookies) are HTTP cookies that can be recreated after they have been deleted. This is possible as they are not stored in the browser as is the case with traditional cookies. Such tracking has encouraged countries such as the UK to enact legislation enforcing website owners to get consent before using cookies.
It is not known yet if this type of regulation will spread to other countries, but as people become more aware of how cookies are used to track there actions online, there is a likelihood that privacy proponents will create measures such as those now being enforced in the UK.
Now that you know a little more about what cookies are and how they work you are more likely understand the implications of their use. Next time you come across an advertisement that looks a little familiar or a website auto fills your log in details you will have a better understanding of how this is being accomplished.