Speaking at the Association of Online Publishers (AOP) conference in London last week, Mr Hart told delegates that the internet is a truly global community and the first information democracy. The web provides billions of pages of information, instantaneous breaking news, and a free, fast competitive marketplace.
"Everyone from billion dollar conglomerates to penniless bloggers all have the freedom to publish and exchange information and ideas." said Mr Hart.
"And from the user point of view, search is the start of online journey. It's as if all the knowledge in the world is just one click away."
But he said that search has now become a tool that can be exploited, with specialist agencies paid big bucks by big business to improve their position in search results.
"This kind of complex distortion is only made available to the big players and will make business in the long term impossible for small firms," said Mr Hart.
"Spend on search is the fastest growing sector in online advertising spend, so money is flowing to just a handful of online web search brands - and to those with only the biggest marketing budgets."
Lorraine Twohill, director of European marketing at Google, disputed that big firms benefit most from Google by paying for technical tricks to improve their ranking in search results.
"Search is driven by complex algorithms. Small sites are often more successful in search results because their content is simpler to index," she said.
Ms Twohill used the example of a search for a ''Ford Focus' car, which returned results for the Ford Focus owners club as well as the corporate Ford site.
"Now little sites are getting cheques in the post that they never had before, because search is generating an income they never had before," she said.
Paul Rossi, publisher of Economist.com, described Google as a 'brand killer'.
"Google says it has the answers, so users will go to the top page result and it doesn't matter where that is. The brand is secondary in the user's mind," he told delegates.
And advertisers should be aware of the potential problems of using Google adverts on sites, said Mr Rossi, warning that Google is 'selling adverts on your site and in your own marketplace, talking to your advertisers and telling them not to use you'.
Despite his reservations, Mr Rossi confessed that Economist.com does run Google ads.
"But if you must sleep with the enemy," he said, "make sure you use protection and make sure you get paid".
• Google's version of the news
Speakers also criticised Google's news tool. Andrew Hart referred to a recent report by web publishing consultant Vin Crosbie which found that 48 per cent of results returned by Google's News tool came from just five sources.
"Search is helping the biggest financial players cement their position," said Mr Hart.
"The web should be more about small players having an equal hand. It is not the case that half the news in the world is produced by a handful of firms."
Ms Twohill of Google responded by saying: "I don't think the Economist and ANM will really be losing sleep about threats to small publishers."
• Public service searches?
One delegate suggested that the commercialisation of search could be the root of these problems for the online publishing industry.
He suggested that the BBC could set up and operate a new open source search facility as a public service, but the suggestion was dismissed by Richard Deverell, head of interactive news at the BBC.
"That would require a vast technical resource that the BBC doesn't have - and I'm not sure we should have," he told the conference.
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