What are the cookies used on gadgets?  -Lydia, 8, Essex, England

Dear Lydia,

A cookie is a tiny file of text that gathers information about you as you browse the web. You might be familiar with cookies if your computer has ever asked if you wanted to turn them on or off.

Let’s say you want to go visit your favorite website. Maybe it is one with cat videos. Humans seem to love cat videos, especially the ones where we are doing something silly.

You open up a web browser and type in the web address, which starts out with H-T-T-P. HTTP is a kind of language the World Wide Web uses to communicate. Browsers can understand this language, too.

The browser uses HTTP to ask a server to send you to the website. Sometimes the website will also send along a cookie, too.

“Your browser eats it and keeps it,” said my friend Aaron Crandall. He is a computer scientist and engineer at Washington State University who told me all about web cookies.

Every time your browser starts a conversation with a website, it is as if they are meeting for the first time. But cookies let a web site know your browser has visited before.

Cookies help remember which language you like to read when you are on a site. They can also remember your email username and passwords. That way you don’t have to log in each time. It can be pretty handy.

Cookies can be a real treat for advertisers, too. For example, cookies can help businesses learn that you like watching cat videos. Then they can use the information about your behavior to advertise other things you might want to buy, like cat sweaters or cat mugs.

Because cookies can track behavior online, they have caused a lot of hoopla, Crandall said. People were a little worried about privacy when cookies were first invented.

“They were a very interesting invention when they came out,” said Crandall. “Highly controversial.”

The reason cookies were invented was actually to make it possible for the website to keep track of a browser when it visited again. This made exiting new things possible on the web, such as shopping online.

Without the cookie, websites couldn’t remember what you put in your shopping cart once you left the site.

Once people learned more about cookies and what they actually did, everyone calmed down a bit. Now, people can go into their privacy settings and change how cookies are used on their device or delete them. People can take a look inside their “cookie jar” to see the kind of cookies that are at work.

While web cookies are tiny files, they play a big role when it comes to how the web works today. Now, if only our gadgets could send us a chocolate chip or oatmeal raisin cookie to snack on while we’re browsing the web, too.

Sincerely,
Dr. Universe

Have a question? Ask Dr. Universe. You can send her an e-mail atDr.Universe@wsu.edu or visit her website at Ask DrUniverse.com.