Mr Hultén, whose company does research for 560 publications in 17 countries representing over 300 million readers, showed how advertising effectiveness, measured in recall and clickthroughs, is declining online, and how mobile and tablet devices are providing very positive indications for advertising effectiveness.

For the traditional internet, "clickers are a diminishing breed," he says. Only 2 percent of audience accounts for two-thirds of all clicks, and 5 percent of the online audience is responsible for 8 out of 10 clicks. The number of people who never click is rising too – from 68 percent in 2007 to 88 percent today.

"Click rates aren't that interesting any more," says Mr Hultén. "Visibility and understanding how a certain ad functions is more interesting. The value of a banner ad is so much more than a click. You can be successful online with very low click rates."

But ad recall online is diminishing too – websites are more cluttered, ads are posted for shorter periods, pages are longer, and rigid web design lets people know where not to look if they want to avoid ads.

There are two important variables for ad success online, Mr Hultén says – frequency and engagement. "Once you get frequent users, you get really high recall. If you don't have frequent users, you need engagement – those who stay on site for a long time."

But what is really remarkable is the recall and click rates for advertisements on the iPad.

"We're in the middle of the honeymoon right now and figures will never be this high again. But they're extremely high – 80 percent recall for an ad, 60 percent for a film, 75 percent for a travel agency ad. But that's not what is really remarkable, it's the 50 percent click rates. It will become lower, of course. Is it the honeymoon, or is it the solution everyone is looking for? It's partly because of the honeymoon, but partly because of the technology and the solutions."