Travelling around New York City at the weekend with my two teenage boys was a reminder of just how globalised our culture has become with shops, music and even art looking distinctly familiar to my young Londoners.

An all-day seminar today on world media seemed to suggest that global journalism has some trans-national trends, too. But as ever, look closer and the cracks appear.

I have spent the day a block away from Central Park at the OSI offices in New York talking media and development with researchers from different continents – albeit dominated by those from the USA. One theme that connected many of us was the business model crisis in commercial news media.

In the US there has been a determined bid to find new support from non-profit sources such as foundations and universities. Hard-bitten free-market hacks find themselves having to convince the public to stump up for what they do.

It’s a kind of mirror image of somewhere like China where the state has been creeping back into news media ownership and control. Despite the opening up of Chinese media over the last decade or so of economic growth there has recently been what one participant here described as ‘renationalisation’.

You could argue that in some parts of Africa and Eastern Europe there has been a similar move as the authorities seek to reassert their influence over the media markets and editorial production. This apparent trend might be due to a combination of factors: economic crisis, new media growth or political reaction.

It’s difficult to generalise across such wide areas and differing national and regional conditions. However, even where it does not threaten media freedom, it makes us ask again, what is the public value of journalism? Does it matter if advertising or a cover price can’t sustain the news media? We in the media keep asking how it be supported in new ways, but what about asking Why?

If the market will not always provide (and let’s be honest, it rarely did provide without some help) then how do we justify the support of the public?

One way is to show that a free and healthy media is good for the economy, society and politics of a country or community. It sounds self-evident (if you are a journalist) but as today’s seminar showed, it ain’t.

It is notoriously difficult to prove whether news media has specific effects. So you might introduce laws protecting journalism into a country. Or perhaps you boost training, or invest in newsrooms or broadcasting infrastructure. And then the economy grows and they stage free elections. Is that down to the increase in free media or would it have happened anyway? Does journalism boost society, or is a healthy media simply a pleasant consequence of a thriving community?

This matters if you are looking to persuade a foundation or a government to invest in media development. In that case you have to show that it is worthwhile investing in journalism rather than, say, health or education.

And as today’s seminar also showed, this is getting harder to prove as the news media itself becomes more complex and networked. Even if you can show that good journalism is good for society, should you then invest in mainstream media or social media? professional training or general media literacy?

This seminar may not have had the answers but it did raise a useful set of questions;