I was probably not alone in being startled by the headline at dn.se, the website for the Swedish daily Dagens Nyheter, on 15 October: "Swinging is our new hobby." That’s right – couples who have sex with other couples.

My first reaction was a feeling of absurdity mixed with distaste. Absurdity because the article is such an obvious result of the paper’s investment in its on-line edition, where material that is purely tabloid in nature – sex, gossip and celebrities – is beginning to gain ground. Distaste because it runs the risk of paving the way for journalism that clashes with the traditions of Dagens Nyheter. Not because DN has ever been prudish – quite the opposite. For many years, the newspaper has championed an open-minded approach to sexuality. But in the past, the article would have been well substantiated, probing and – above all – predicated on an actual social phenomenon.

Ev...