A cookie, also known as a web cookie or a browser cookie is a small piece of data transmitted to a user’s web browser while they are browsing a website. The website will recognize the user next time they return using the information stored in the cookie. These tiny files – cookies have a maximum length of 255 characters and cannot take up more than 4 kilobytes of disk space – are very useful as they can remember your preferences when you return to the site but have come under scrutiny because of privacy concerns. This is why we are seeing many websites now asking us to click to accept their cookies and cookie policies. The problem is that many people don’t know anything about them – in a 2011 survey conducted by the Department of Culture, Media and Sport in the UK, only 13 percent of respondents indicated that they understood how cookies worked. Read on to find out…
First party vs third-party cookies
A first party cookie is a cookie from the website that the user is visiting. A third-party cookie is from an associate of that website, often an advertiser or company who gathers statistics about Internet usage. To explain, when you visit amazon.com and sign in you will receive a number of cookies from amazon and a couple from doubleclick.net and cloudfront.net! Cloudfront is an Amazon subsidiary involved in content management and Doubleclick is a company that provides technology that powers Internet advertising (banner ads etc.) – Google bought Doubleclick in 2007 for $3.1 billion. The advertisers are using these cookies to build up a browsing history of the user across all the websites this advertiser has footprints on.
Cookies perform lots of useful jobs, they can remember your username and password so you don’t have to keep typing it in when you return to a site. They can also store form data or keep track of your shopping cart items when buying online. Some cookies only last for the duration of a single visit – these are called session cookies, however most cookies are what are called persistent cookies. These remain stored on your computer and expire after a set period of time, so they are there the next time you return to the site. The average expiration for persistent cookies is one year but it can vary wildly – the doubleclick.net cookie on my computer will expire in two years – the amazon.com cookie expires in 2033! Next time, we’ll look at how to manage cookies on our computers.