Google advertising: How did it know I like hats?

If you haven't read the 2,000-word email from Google, in short – it's changing its privacy settings. Time to panic? Not really, says Rhodri Marsden, but it will make its advertising scarily accurate

Google’s internal systems have altered, so information it gathers while you’re using one of its products – for example the Google search engine – can now be used to tailor your search results when you’re using another. So if you’ve been searching for hats (ALAMY)

Back on 26 January, a courteous email dropped into the inboxes of millions of people who use Google products. It explained that the company was about to distil 60 different privacy polices for its services into one "easy to read" document – not that many of us bothered to read it, what with it being more than 2,000 words long. EU officials did, though, and they weren't impressed, reporting that the repercussions were "too difficult even for trained privacy professionals to understand".

While Google maintains that its privacy principles remain unchanged, this new policy appears to fall foul of the European Directive on Data Protection. The EU Justice Commissioner Viviane Reding told the BBC yesterday that data-protection agencies had found that "the new rules are not in accordance with the European law".

So what's changed? From yesterday, Google's internal systems have altered, so information it gathers while you're using one of its products – for example the Google search engine – can now be used to tailor your search results when you're using another. So if you've been searching for skydiving lessons, skydiving videos may confront you next time you use Google's video service, YouTube.

The change is partly down to Google's rapidly accumulating size; while Facebook is one unified service covered by one policy, Google has branched into so many directions that you can't really blame it for wanting to integrate and streamline the data flow.

But this isn't just about overzealous administration. Google's revenues are directly proportional to the relevance of the search results and advertisements it displays to us, and the company is currently seeing huge competition from Facebook and Twitter as the web becomes driven by the "wisdom of friends".

So Google is in a race to stay relevant – but while we appear to be happy to surrender information to Facebook under the auspices of sharing stuff with our mates, Google doesn't find it quite as easy to get to know about us. And so when it makes changes such as this in order to build a better profile of our interests, it meets huge resistance. It points out that it doesn't share our browsing habits with anyone else, but we don't care. We don't like the idea of Google knowing what we're up to.

Should it bother us so much? After all, the alternative to seeing advertisements and search results that are tailored to our interest in, say, vintage cars, is being confronted with advertisements for something we might not care about, such as ballet classes. Yes, we may find it slightly creepy when our interests appear to follow us like obedient puppies around the web, but Google is right in that the more it knows about us, the better job it will do in giving us relevant links. In most cases, the information it gleans is totally benign. But in some it can be a problem – for example, if a teenage girl becomes pregnant, searches for abortion services and then unwittingly reveals that to her family via insensitive advertising placement.

Even if we give Google the benefit of the doubt, we could still take issue with the way the change has been implemented. No one expects Google to flag up serious privacy concerns when it tweaks terms of service, but the difficulty of opting out of its data-collection mechanism is viewed by many as infuriating. While browsers such as Firefox and Safari offer a "do not track" option, Google has been slow to implement it in its Chrome browser; it has promised that this will happen by the end of the year – and, perhaps more importantly, that its own online services will honour "do not track" requests from our browsers.

If Google ever dares to hint that we don't have to use its services if we don't want to, there's widespread outrage. But that's down to equally widespread ignorance of the cost of using its products. Google does not exist as an altruistic, charitable concern; services are provided free of charge, but there is a cost: snippets of our personal information. If you aren't happy to reveal these, there are other search engines available.

Or, as the satirical newspaper/website The Onion once brilliantly suggested: "Google opt out feature lets users protect privacy by moving to remote village."