Imagine living with no memory: every person you meet, even your mom or dad or best friend, you would have to ask them their name, their relationship to you, and other questions to get up to speed.

Websites have the same problem: when you re-visit their site, they don’t remember you. They use cookies but not the way we use cookies, to enjoy ourselves and feel better.

Websites use cookies to help them remember things. These cookies are created, updated, and deleted with web browsers. Website cookies are small bits of data, called a text file, that sit on your computer. Websites some times write out information to these data cookies so when you visit again, the website can pick up the cookie it left, read a little about you, then use the information as you browse the website. In most cases, these cookies are very useful for repeat visitors to a website.

There are two kinds of cookies: those that last only while you are on a website (called session cookies) and those that last between visits to a website (persistent cookies). But are also called http cookies but they serve different purposes.

In the same way eating 500 real cookies at one go can be a problem, for most people, the cookies a website leaves behind also can be a problem. Advertisers like to leave cookies to track where you go and, some times, what you do. It’s reported the US spy agency, the National Security Agency (NSA), also reads advertiser cookies on computers to track people. The rules for how and when cookies are used depends on the country you live in and, in some countries, the company that places the cookie.

For example, rules in the United States are fairly loose for what advertisers can do. Rules for Europe are much tighter. Yet Americans and Europeans alike can go to Google.com and use their site to find, browse, and erase any personal history the Google search engine has collected about the search terms they used in Google’s search engine. Google’s data about your search efforts is stored on their computers but a cookie helps them identify you.

Should you turn cookies off? Probably not if you log in to some websites. It is common to use cookies as part of the log in process and to authenticate you during your session on a website. Instead, web browsers have some form of Preferences tab or link where you can see all cookies currently managed by the browser. You can go through the list and delete cookies from advertisers or other sources, if that bothers you.

Here is an example of browsing cookies in the Firefox web browser:

Notice the _ga bit? It’s likely that is a unique ID to track my activity through Google Analytics, an online software tool website owners use to track activity on their sites. Because the site is the 3D object warehouse for SketchUp, software I use and like, this cookie does not bother me.

In short, cookies are like anything online. You should know about them. Cookies can make your online life easier. But they also should be watched over time to ensure your privacy.

If you are interested, this magazine site uses cookies but in a limited way. Cookies are used for subscribers who log in, to help remember them and save having to log in later, and for site activity reporting. However, I only track simple activities: the number of unique visitors compared to repeat visitors, the number of pages viewed, time spent during each visit, and similar data to give me a rough idea how the magazine site is used. I don’t, for example, track activity through the site on a visitor by visitor basis. I find that creepy.

Nor is it necessary. Readers who email me with questions and suggestions for content provide me with more insight than Google Analytics ever has in over 12 years of using these tools.

Learn More

HTTP Cookies

http://en.wikipedia.org/wiki/HTTP_cookie
http://www.allaboutcookies.org/

Cookies and the European Union (EU)

http://ec.europa.eu/ipg/basics/legal/cookies/index_en.htm
http://www.theeucookielaw.com/
http://cookiepedia.co.uk/cookie-laws-across-europe

NSA uses Google Cookies to Pinpoint Targets for Hacking

http://www.washingtonpost.com/blogs/the-switch/wp/2013/12/10/nsa-uses-google-cookies-to-pinpoint-targets-for-hacking/

(Real) Cookies

http://allrecipes.com/recipes/desserts/cookies/
http://www.slate.com/articles/life/the_completist/2012/09/pepperidge_farm_cookies_what_i_learned_about_life_from_the_milano_the_verona_the_geneva_.html
http://www.nytimes.com/2008/07/09/dining/09chip.html?pagewanted=all&_r=0