Ethan Zuckerman is a fellow at the Berkman Center for Internet and Society

"The internet has not become the great leveller that it was once thought it could be," according to Harvard academic Ethan Zuckerman.

Mr Zuckerman was speaking at the TED Global (Technology Entertainment and Design) conference in Oxford.

He said that the web was now contrary to the original utopian vision and users focused on information from a handful of wealthy countries.

"It's making us 'imaginary cosmopolitans'," he told delegates.

Social networks, he said, made the problem worse with the majority of people sharing information with folk who share their world-view.

"We think we're getting a broad view of the world, because it's possible that our television, newspapers and internet could be giving us a vastly wider picture than was available for our parents or grandparents," he said.

Of the 250m websites, there are over 80m active dot com sites

The internet celebrates a landmark event on the 15 March - the 25th birthday of the day the first dotcom name was registered.

In March 1985, Symbolics computers of Cambridge, Massachusetts entered the history books with an internet address ending in dotcom.

That same year another five companies jumped on a very slow bandwagon.

It took until 1997, well into the internet boom, before the one millionth dotcom was registered.

"This birthday is really significant because what we are celebrating here is the internet and dotcom is a good, well known placeholder for the rest of the internet," said Mark Mclaughlin, chief executive officer of Verisign the company that is responsible for looking after the dotcom domain.

"Who would have guessed 25 years ago where the internet would be today. This really was a groundbreaking event," he said.