one of the most interesting aspects of the relaunch is that they have tagged every single Guardian/Observer travel article - for SEO [search engine optimisation] purposes and to enhance its behavioural and contextual advertising.

more here

contextual advertising: only displays banners/buttons/skyscrapers/sponsored links against relevant content. an article on Spain will see the user served only Spain-related ads, such as spanish hotels, carriers with routes to spain.

behavioural advertising: Guardian Unlimited will track your user behaviour on the site and then only serve relevant ads it thinks you are likely to click on.

eg. over time on GU if you read Leeds football results, read some action movie reviews, check out certain destinations on the travel section, read the weather for yorkshire, then the ad servers will display ads that it thinks suit your demographic - young, male, northern-based, etc, etc - such as DVDs, clothes, film releases, cars. that way you would probably not see any ads for pefume, lingerie and women’s magazines.

it does conform to certain sterotypes, of course, but it’s incredibly clever and the conversion rates for ads are much improved.

hope that all makes sense.