There’s little question that a big drain on productivity is worry. Many of us tend to worry about things that are out of our control. One item that I think too many people worry about is browser cookies. Browser cookies are neither good nor bad. If you were to remove all cookies, you’d probably find your internet experiences to be less enjoyable.

What are Browser Cookies

A browser cookie is a small text file that a web server sends your web browser when you request a page from a site. This text file is no larger than 4k and stores specific data elements. There is no programming code in these files. If you were look at the cookie with a tool such as the Firefox extension, View Cookies, you would see a panel that listed the cookies our server issues.

From the screen snap, you can see there is a structure that cookies share. Each cookie has values for six fields:

• Name
• Value
• Domain
• Path (the “/” means the cookie is valid anywhere on that domain.)
• Expires
• Secure (used for cookies that require a SSL connection)

The lower part of the panel shows the specific details for one of our cookies called “fontSize”.

How Do I get Cookies

One question people often ask is how they even got these cookies. This is all handled on the backend between your web browser and the server of the web site you’re visiting. When you request a page from a site such as ours, the web server looks for cookies from our domain timeatlas.com on your computer. You can see in the screen print above, that there is a field where the domain name is captured. Our web server only reads cookies that match timeatlas.com. As example, our server couldn’t read your Yahoo! cookies and the Yahoo! servers couldn’t read the timeatlas.com cookies.

If the web server finds its domain cookies, it will use them. As example, it will use the pageWidth and fontSize cookies to adjust the screen width and font to your preferred state. If it doesn’t find any cookies, it will create them. This can be controlled by your web browser as you may prevent cookies. Some people also have software programs that manage cookies.

Different Types of Browser Cookies

There are some important differences between cookies based on expiration and domain. A web server can issue two types of cookies based on time called session cookies and persistent cookies. Cookies that expire once you log off or close the browser are called session cookies. These all display “session” under the Expires column. Online shopping carts may use session cookies to track items in your basket. These cookies are stored in memory and not on your hard drive.

A persistent cookie is one, which has a date expiration. The expiration date is issued by the web server. In the example above, you can see our fontSize and pageWidth cookies are persistent cookies that last a year. This means the user doesn’t have to worry about adjusting their screen preferences for a year unless they delete the cookies. In some cases, persistent cookies are set for a very long time. These types of cookies can help a webmaster find out who is a new viewer and who is a returning viewer.

Aside from expiration, there is another distinction based on domain. Again, looking at the screen snap you can see that all our cookies show a domain of timeatlas.com. If the domain name in the Domain field matches the issuing site’s domain name, it is known as a First Party cookie. These tend to be trusted cookies as you have a relationship to the site unless you’ve been infected by some spyware or Adware.

If you were on our site and we served a cookie from XYZ.com that would be considered a Third-Party cookie. You generally don’t have a relationship with this company. These types of cookies are often scrutinized as people want to know who is this other company. In some cases, there is a relationship to the company. As example, if this site were part of a publishing company that had many properties, the server might issue a third-party cookie in the parent company’s name such as timeatlas.publishingcompany.com. Other examples might be cookies issued by a web analytics company on behalf of the site you’ve visited.

One type of third-party cookie that raises eyebrows belongs to ad networks. Some websites use the services of ad networks to deliver banners and other types of ads. These sites may set a third party cookie that can be read by other member sites to deliver the ads. When I encounter these types of cookies, I like to analyze their Privacy Policy with a tool like EULAlyzer.

Why Cookies are Used

While many people equate cookies to ad delivery or tracking, they can do more. Cookies are also used to:

• personalize a site
• authenticate you to a site requiring a username
• track affiliate leads
• analyze web traffic

This site sets cookies for personalization and analytics purposes. If you look at the highlighted example above, you see the cookie named “fontSize”. This is an example of a cookie offering personalization. If you were to use the button in the top right corner of this site, the server would set a cookie with your new preference rather than the default value.

The part that often scares people is the web analysis. In our case, the bottom four cookies starting with an underscore are used for web analysis. Some people mistakenly think that cookies allow webmasters or some entity to track all your movements throughout the web. They believe the moment you leave my site, I alert Amazon and tell them you’re on your way to buy that book on Outlook. At same time, Google is telling me that your second cousin, on your Dad’s side, is heading my way to read about an Excel tip.

Like most stories, there is some truth to the one above. I can tell if a user was referred to this site by Google and they were searching for an Excel tip. But it’s not a cookie that tells me that info. That’s just part of the info that is written to the web server logs. I also can’t tell that you’re on your way to Amazon to buy an Outlook book. However, if I was an Amazon affiliate and had a link for that book on this site that you clicked, Amazon might set a first-party cookie when you arrived indicating timeatlas.com was the source. This tracking cookie is the mechanism by which many affiliates are paid. By deleting these cookies, you could be impacting future commissions for someone.

Where to Find Browser Cookies

Your system only saves persistent cookies. Each browser manufacturer sets their cookie location. This is why some sites look different in different browsers. You may have set your personalization for a site using Firefox, but not done the same exercise using Internet Explorer. Cookies are not shared across browsers. The same rule applies if you delete cookies too.

If you’re using Internet Explorer, you will have a separate cookies folder that lists all your items. This folder is found at:

C:/Documents and Settings/[your user name]/cookies

One item that scares people with Internet Explorer is the cookie name includes your username. As example, the cookie for our site might show as This e-mail address is being protected from spambots. You need JavaScript enabled to view it . This user names, "jr", does not get sent to a server. This is Microsoft’s way of separating multiple users on one computer.

If you’re using Firefox, the cookies are all in one file called cookies.txt. This file is found at:

C:/Documents and Settings/[your user name]/Application Data/Mozilla/Firefox/Profiles/[profile name]/cookies.txt

Personally, I don’t worry about first-party cookies if I know the domain. Hopefully, someone on the other end of the equation reading their web analytics will make good decisions based on what they’re seeing. I know I look at the data as it helps me see what people are interested in learning. I’m less likely to keep a third-party cookie and often try to find out more.

Related Internet Privacy Articles:

• Understanding Web Server Log Data
• Internet Privacy Questions and Considerations
• How to Erase Google Web History