Arguments over the prospects for modern-day advertising - on social networks, video games and mobile phones - are raising questions about a revenue stream on which many telecommunications, media and technology groups are pinning their hopes.

In debates at the World Economic Forum in Davos last week, enthusiastic technologists and advertising agencies pronounced that 2008 would be the year in which such marketing techniques would become mainstream.

But sceptical media owners disputed their growth predictions, questioning consumers' appetite for advertising campaigns in such new areas.

"The [supposed] solution to everything at the moment in the digital space is adsupported," Sir Howard Stringer, chief executive of Sony, told the Financial Times. "While advertisers are happy to talk that up, there is a limit to the amount of money available."

"The business model is not there today [for mobile advertising]," said Jeff Zucker, chief executive of NBC Universal.

Bobby Kotick, chief executive of Activision Blizzard, was similarly sceptical about advertising-funded video games, saying: "It's early days. I wouldn't go in that direction myself."

Advertisers are hoping that incursions into media where consumers are spending more of their time will help engage audiences that are drifting away from radio, print and television.

High hopes for new forms of advertising have fuelled a series of acquisitions of digital agencies by established advertising groups, and spurred investment in mobile advertising start-ups such as Amobee and Ad Infuse.

The debate has become central to the US writers' strike, where authors and studios are arguing over how digital revenue streams should be shared.

The digital optimists were supported at Davos by Google, the search engine group, which argued that forecasts of mobile advertising revenues reaching $1bn by 2012 were too low.

"It's the recreation of the internet, it's the recreation of the PC story, it is before us - and it is very likely it will happen in the next year," Eric Schmidt, chief executive, said of the location-based advertising made possible by the mobile internet.

The community aspects of social networking sites such as Facebook, where friends swap recommendations, are also exciting advertisers, with one panellist in a private debate claiming these could make Facebook a more important advertising medium than Google.

Facebook's experiment with targeted advertising, Beacon, initially fell foul of users' privacy concerns, but marketing executives blamed this on rushed execution.

"I think they handled it badly. Consumers are incredibly open to marketing messages as long as it gives them something," argued Nigel Morris, chief executive of Isobar.

David Kenny, chief executive of Digitas, said such attempts to harness online communities would take off this year.

The digital agency, taken over by Publicis a year ago, was already working with Yahoo Communities and with Google's Open Social effort to standardise applications for social networks, he said. "We believe the tools will be ready in six months, so we're working on the content," he said.

Mr Kenny admitted that the business model for mobile advertising was "still a challenge" for content owners, but he said: "Sony, NBC, Google and us all need to work together" to create a new model.

Advertisers cited research showing that consumers found mobile, video game and social network advertising intrusive, but many were willing to put up with it in exchange for free content.

Mr Morris argued that consumers were well used to television advertising but were still adjusting to new marketing methods.ITV

Sir Howard was less convinced, saying "young people don't like advertising very much" but he admitted business models were changing fast.

www.ft.com/davos