Opinion: Time to shed light on the dark art of behavioural advertising

Last month, I was looking at hotels for a trip to Reykjavik. One of the websites I visited was Hotels.com. A week later, I was reading an article on the Guardian’s website and noticed a Hotels.com advert for a hotel in Reykjavik on the page.

Was this simply a coincidence, or based on my Google search history? Or had I misunderstood how behavioural advertising works? Was the ad served up by Hotels.com, based on my recent visit to the Hotels.com website?

The Guardian is a member of an online behavioural advertising system provided by a company called Audience Science. Audience Science has a number of partners, each of whom shares information on your use of their websites to allow these commercial partners to provide targeted advertising.

At some point, I must have accepted a cookie in relation to the Audience Science system, but the pop-up box would not have provided any information on how the cookie would be used. What is worrying from a user’s perspective is that Audience Science’s list of partners will continue to expand. This means that you could be using one website unaware that your browsing habits could subsequently influence advertisements served up on another.

The Guardian also has a commercial partnership with an organisation, Criteo, that specialises in “retargeted advertising”. Because the set-up is so opaque, it is difficult to identify which organisation provided the Hotels.com advert, but I believe it was Criteo.

Here is what the Guardian’s privacy policy says about it:

“For example, if you have visited the website of an online clothes shop you may start seeing ads from that same shopping site displaying special offers or showing you the products that you were browsing. This allows companies to advertise to website visitors who leave their website without making a purchase.”

Again, I don’t remember opting in to this system. Clearly, I must have accepted a cookie at some point (or passively accepted Hotels.com’s privacy policy) – but I wasn’t aware that Hotels.com was going to chase me around the internet.

According to Criteo, the only way of opting out is to accept a permanent cookie. So if you don’t like cookies, but also don’t like your internet usage being tracked – tough.

I suspect that I am not alone in not fully appreciating to what I have opted in. Cookie warnings do not currently explain how your data is used. Under new European laws, behavioural advertising providers have until next May to introduce systems that require users’ express (and informed) consent before cookies can be installed. Given the lack of transparent information available, I look forwards to the clarity that this will bring.

Martin Sloan, associate, technology group, Brodies LLP