Original URL: http://www.theregister.co.uk/2010/03/26/google_remarketing/

Google remarkets behavioral ad eyeball creep

The ad that stalks you

By Cade Metz

Posted in Media, 26th March 2010 00:09 GMT

At the very least, it's yet another demonstration of Google's uniquely creepy ability to control what you see on the interwebs.

On Thursday, Mountain View formally announced a behavioral targeting scheme that allows a third-party advertiser to place a piece of Google code on its website that will track your visits to the site and trigger related ads when you hit any one of the hundreds of thousands of other sites in Google's web-spanning ad network. According to Google, its "content network" - a world of sites that display ads via Google AdSense - reaches 80 per cent of all net users.

Google calls the scheme "remarketing", and it has been in testing for over a year. According to today's blog post from Google, a beta was introduced last March when the company first announced it would be targeting ads on its ad network "based on the types of sites you visit and the pages you view".

Google's original blog post focused on its intention to target ads according to "categories of interest" it assigned to your browser using your surf history on its ad network. But it also included a brief mention of what it's now calling remarketing. In that March 2009 post, Google referred to its behavioral targeting schemes as "interest-based advertising":

Interest-based advertising also helps advertisers tailor ads for you based on your previous interactions with them, such as visits to their websites. So if you visit an online sports store, you may later be shown ads on other websites offering you a discount on running shoes during that store's upcoming sale.

This is separate from Google's effort to observe your behavior within its ad network. With remarkering, advertisers place a separate tracking bug - a "remarketing tag" - on their sites. As today's post says:

Let’s say you’re a basketball team with tickets that you want to sell. You can put a piece of code on the tickets page of your website, which will let you later show relevant ticket ads (such as last minute discounts) to everyone who has visited that page, as they subsequently browse sites in the Google Content Network.

Today's post also explains that an advertiser can trigger ads across Google's ad network based on your visits to the advertiser's YouTube channel or its YouTube homepage ad.

It's unclear whether Google merges browsing data collected on its ad network with data collected by remarketing tags. And it's unclear how long Google stores its behavioral ad targeting data. The company has not responded to our requests to discuss its new scheme.

As of today, remarketing is available to all advertisers.

The cookie Google uses to track behavior and serve ads on its ad network is the same one the company uses on its DoubleClick ad platform. This was not mentioned in Google's original behavioral targeting post, but the company later confirmed with The Reg that this was the case.

Asked whether it shared data between the two ad platforms, Google indicated it did not. "Although we use the same cookie, our data use rights vary per product according to our contracts with our customers," the company told us at the time.

Yes, Google's behavioral targeting brings to mind the ill-fated schemes from the likes of Phorm or NebuAd. But there are significant differences. Phorm and NebuAd tracked users by setting up shop within third-party ISPs, observing your data at the network level. Google, by contrast, is tapping the pages of myriad advertisers and other partners. It's exploiting a relationship - the one between you and a website - that's different from your relationship with an ISP.

But even without the help of an ISP, Google's potential for data collection is enormous. Again, it's unclear how long Google keeps its behavioral targeting data or to what extent data from disparate sources is merged - or will be merged in the future. AdSense and DoubleClick data may not be merged today, but now that they use the same cookie, it would be trivial to do so.

Google says you can opt out of remarketing from its Ad Preferences Manager, introduced last March in tandem with its behavior targeting schemes. This is a cookie-based opt-out, but Google also offers a browser plug-in that opts you out of its behavioral targeting.

In both cases, the opt-out disables the ad network cookie that Google places on your machine. Presumably, this will also mean that you will not be tracked by its remarketing tags, but this too is unclear. ®