Wednesday, September 14, 2005

Cookies -- The Web Browser Kind

I received, too long a while back, a question about cookies. What are they? Are they bad? Should they be deleted?

First, what is a cookie? A "cookie" is, essentially, a piece of data that your browser stores on your computer that is maintained for a web site. The website interacts with your browser to store this information so that it can be retrieved later. For example, a cookie could contain your login name to the web site, or your preferences for how you want the web site to display data to you. It can also store where you went in the web site last time you were there. The primary use of cookies is to allow a web site to know who you are when you visit the site.

Cookies on their own are benign. They do no damage. They just store information.

Why the term "Cookie?" Well, when you see computer terms, remember that the people who invented them are/were very "technical." These are the guys who created the term "bit" for "Binary Digit," which is fine, but then had to go and make a "byte" eight "bits", and a "nybble" four bits, or half a byte. The derivation is unclear, but visualize a web site handing your browser a real cookie and saying "hold this; I will ask for it later." When you visit the web site later, the site asks "say, do have that cookie I gave you? Let me take a look at it." The site then looks at the cookie and says "yeah -- that's right. This is you. You searched for 'X' last time, and your login is 'Y', and... etc."

Why are they needed? Well, as mentioned above, the answer is that it allows a website to remember the browser (i.e. your computer) between visits. For those sites that offer personalized content, like "my yahoo" or various newspaper, magazine, and commercial sites, this is very useful. In fact, cookies make life easier for you as well as the sites that use them, since they prevent you from having to continually tell the site who you are and what you want.

However, some cookies, called tracking cookies, are used to ID you for advertising or marketing purposes. Advertising sites that display ads and various marketing information sites keep cookies to ID you, and therefore know which ads you have seen, which sites the ads were on, which ads you clicked, etc. They know the types of sites you visit, and sometimes where in the site you went there. They know the date and time you visited. They probably don't track you personally, but they know your browser.

This activity is what people object to who object to cookies. The proponents of this use of cookies say that they allow the user (i.e., you) to have a "better online experience" since the information they keep on you is used to fine-tune the ads and sometimes the content you see. The detractors charge that this information is collected without your knowledge, without explicit permission (you gave implicit permission when you allowed your browser to use cookies), and is an invasion of your privacy. They don't necessarily trust that the information collected is not used for nefarious purposes.

Will it kill you to have this information kept? In reality, no, but it is a bit "creepy" to know you are being watched. Advertizers and marketing companies can't track people watching TV or listening to radio, but they sure can track you with a web browser, and they do.

As a result, these are the cookies you will probably want to get rid of.

How do you do that?

Well, one way is to have your browser delete them. This is a shotgun approach. You will lose all cookies, including the ones you may want to keep around.

Another way is to use an anti-spyware or anti "adware" program that knows which cookies are tracking cookies and which are not. This is the better approach. This is a field that is evolving every day, so I hesitate to recommend a specific program, but I have found that Lavasoft's Ad-Aware and Spybot are two good tools. I have used both to success. There are other companies that have this - even Microsoft has an anti-spyware product in beta testing.

These cookies are not as harmful as viruses, so I do a scan every other week or so.