A ruling forcing Google to remove search results has been described as "astonishing" by Wikipedia founder Jimmy Wales.
The European Courts of Justice ruled on Tuesday that an individual could demand that "irrelevant or outdated" information be deleted from results.
Mr Wales said it was "one of the most wide-sweeping internet censorship rulings that I've ever seen".
Google has said it is looking into the implications of the decision.
Mr Wales, speaking to BBC Radio 5 live, said: "I suspect this isn't going to stand for very long.
"If you really dig into it, it doesn't make a lot of sense. They're asking Google... you can complain about something and just say it's irrelevant, and Google has to make some kind of a determination about that.
"That's a very hard and difficult thing for Google to do - particularly if it's at risk of being held legally liable if it gets it wrong in some way.
"Normally we would think whoever is publishing the information, they have the primary responsibility - Google just helps us to find the things that are online."
He added: "I would expect that Google is going to resist these claims quite vigorously.
"I think they would be foolish not to because if they have to start coping with everybody who whines about a picture they posted last week, it's going to be very difficult for Google."
On Tuesday, a top EU court ruled that Google must remove search results at the request of ordinary people in a test of the so-called "right to be forgotten".
The case was brought by a Spanish man who complained that an auction notice of his repossessed home on Google's search results infringed his privacy.
Google said the ruling was "disappointing".
The ruling has provoked a flurry of reaction speculating on the wider implications of the EU's decision.
In the Guardian, journalist James Ball described the ruling as "either an eerie parallel with China's domestic censorship of search results, or a huge incentive for tech investment to get the hell out of Europe".
He added: "Neither, presumably, is a remotely desirable result."
Conservative MP and former shadow home secretary David Davis backed the court's decision, saying: "The presumption by internet companies and others that they can use peoples personal information in any way they see fit is wrong, and can only happen because the legal framework in most states is still in the last century when it comes to property rights in personal information."
In the US, Slate's Lily Hay Newman argued that if taking down search results became the norm, another problem may arise.
"A case could be made that this may give people a false sense of security," she wrote. "Sure, if you remove something from Google or Bing, most people won't be able to find it anymore. But it still exists, and interested parties may be able to find it."
Also looking at implications beyond Europe, Canada's Financial Post quotes lawyer Geoff White as saying "I think some privacy advocates might leverage this decision to recommend that Canada follow a similar path, particularly with minors."
Coverage in the Washington Post reflected the view that the ruling would put Europe firmly at odds with the more hands-off approach taken by the US government on data privacy.
A different perspective, and one certainly not expressed by Google, was offered by law firm CompactLaw: "We would argue that the 'right to be forgotten' is a fundamental right for living a life online.
"We would also argue that enshrining this right will actually encourage more sharing and personal content - so will actually benefit media companies like Google."
European Commission vice-president Viviane Reding, who has led the EU's data privacy efforts, took to her Facebook page immediately after the ruling.
"The ruling confirms the need to bring today's data protection rules from the 'digital stone age' into today's modern computing world where data is no longer stored on 'a server', or once launched online disappears in cyberspace," she wrote.
"This is exactly what the data protection reform is about - making sure those who do business in Europe, respect European laws and empowering citizens to take the necessary actions to manage their data."
And despite first being published in 2012, this assessment of the key issues around the "right to be forgotten" was circulated widely on social media after the ruling. In it, professor of law Jeffrey Rosen concluded that whichever way any future law evolved, "it's hard to imagine that the Internet that results will be as free and open as it is now".
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