Browser cookies are an interesting topic, because it seems that anyone who knows anything about them has an opinion. Privacy-minded folks probably won’t give them a good review. Online merchants will tell you they’re invaluable. Most people probably fall somewhere in the middle.

If you don’t know much about browser cookies, read on for a brief description of what they are, what they can do, and what to look out for.

What is a browser cookie?

Browser cookies (AKA “cookies”, or “web cookies”) are text files that reside on your computer. Cookies get onto your computer by visiting a website that sets a cookie on your machine. A browser cookies lifetime can be updated by the website that sets the cookie, but as a user, you can always delete cookies at will through your web browser.

What kind of websites use browser cookies (and why)?

Any type of website can use cookies. If you’ve ever been to sites like Google, eBay, or Amazon then your computer has received a cookie. Some sites use cookies to keep track of preferences, such as what color you want a theme to be, or if the login mechanism should remember your username so you don’t have to keep typing it in. A cookie can also be used to keep track of what’s in your online shopping cart so the website can check you out faster or suggest other items you may be interested in.

Since anything that can be described in text can be set in a cookie, the possibilities are endless for what can be put in a browser cookie. The results are in a key=value format, but the key and value are determined by whomever writes the code, so they can be anything; the content can even be encrypted if the developer wants it to be.

What concerns should I have regarding browser cookies?

Can a browser cookie infect you with a virus or spyware? No, not directly. Browser cookies aren’t executable like software programs; they’re just text files. However, they can be used to track things you see, click on, etc. and are therefore technically a privacy concern. If you are concerned with remaining completely private and anonymous on the Internet, cookies probably won’t be your favorite topic.

Even though browser cookies themselves can’t cause problems, cookies can be used as part of the overall process in a malicious scheme. Cookie hijacking, where a third party intercepts your browser cookies on a non-secure connection, is a possibility, and that can lead to things like spyware and loss of privacy.

Are browser cookies bad? Are browser cookies good?

The answer, it seems, depends on many factors. Who (or rather, what website) wrote the cookie? What are they using it for? Is the information kept for use by the site only, or is tracking data passed to third parties? Does the website require cookies for the site to function? Does the website put sensitive information about you or your browsing session in the cookie data?

You can crack open any cookie on your machine to view the contents (remember: they’re just text files), so if you’re really concerned about what’s in a particular cookie, check them out in your browser and see what’s going on. Most cookies are pretty safe, especially those from the Amazons and eBays of the world, but you never know until you start poking around. If you’re really concerned, just be sure to keep your antivirus and/or antispyware software up-to-date and be careful about where you’re surfing. If you do those things, chances are pretty good you’re going to be OK.