What’s a cookie (computer variety)?

Cookies are much talked about and are the trigger for all sorts of annoying pop up messages on websites, but what really are they?

They are little text files which a website or other online service puts on your device to record something you have done. Often this can be very useful, such as recording that you have logged in securely from that device. This means that when you, or someone pretending to be you, tries to login from a completely new device, the system can run extra security checks to protect you.

Cookies are also often helpful in ensuring the smooth running of services, such as ecommerce sites, and in particular ensuring that an interruption to what you are doing does not result in you losing your order, ending up paying twice or other similar mini-disasters.

But there is also a more controversial side to them which is to track what you have done across multiple sites. Suppose you visit website A and it puts a cookie on your machine. Then you visit website B, owned also by the company who runs website A, and it takes a look at your cookies and sees that you previously were on site A. That way it can tailor its content or ads.

Again, this can be innocuous and even welcome, but when the cookie placement and tracking is being done by big advertising networks via huge numbers of sites online it means what you’re doing online can be tracked across many sites and that data parcelled up to sell adverts aimed specially at you. It is how Amazon, for example, runs ads across many sites promoting that product which you looked at on their site but didn’t buy at the time (aka retargeting).

That sort of data tracking leads some people to prefer to block cookies, and hence the popularity of software such as Ghostly which blocks them for you. It can also speed up your browsing but the downside of blocking all cookies is that many perform useful functions such as improving the security of your online accounts.

The naming of cookies, by the way, was an innocent piece of tech culture. However, there is no doubt that cookies are far more acceptable to users thanks to their cuddly name than if the technology had been christened, say, ‘personal data tracking files’. Those pop up messages about cookies would get a very different reaction if they asked ‘do you want to block personal data tracking files?’

I wrote this piece for our weekly Digital Inspiration email at Teneo Blue Rubicon.