"Search engine service providers are not responsible, on the basis of the (EU's) Data Protection Directive, for personal data appearing on web pages they process."
Lawyers agree that Google's search algorithms, which hunt and list weblinks based on how relevant they may be, would not be in a position to "know" whether data was personal or not.
"A search engine is just a tool," said Eduardo Ustaran, a London-based lawyer from Field Fisher Waterhouse. "The nature of that information is irrelevant. It is just ones and zeros."
A final judgment on the case is expected before the end of the year. Judges in the European Court of Justice are not bound by an advocate general's opinion, but follow such recommendations in the majority of cases.
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The case stems from a complaint by a Spanish man that a public notice announcing that his home was up for auction after being repossessed infringed his privacy and should be deleted from Google's search results.
His case is one of 180 similar examples in Spain in which people have sought to have content deleted from Google searches. The other cases are on hold pending the EU court's decision.
The original auction announcement was from a Spanish newspaper, which said it was under a legal obligation to publish the notice.
Google welcomed the advocate general's opinion, saying it supported the company's view that deleting such content amounted to censorship.
"This is a good opinion for free expression," said Bill Echikson, Google's head of free expression in Europe, the Middle East and Africa, said in an emailed statement.
But Internet companies may be disappointed at the opinion that they should follow EU privacy law even if the data is handled outside the European Union. Many internet firms maintain that handling data outside the 27-member bloc means they are not subject to EU privacy law.
The advocate general said that even the presence of an advertisings business, which is fundamental to the model of companies such as Google and which targets people in Spain, means they must follow EU law. If that view is upheld by the ECJ, it could put search firms under more pressure to protect the data of privacy-hungry Europeans.
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The European Union is finalizing a major overhaul of its 20-year-old data protection law that would make internet companies follow EU rules if their services target European consumers.
The overhaul is part of a push for increased data privacy in Europe, which has gained urgency after revelation of a large-scale U.S. Internet spying program targeted at foreigners.
The EU overhaul is also intended to give citizens "a right to be forgotten" even though it is not yet clear in what circumstances that right could be invoked. The advocate general said such a right does not exist in current legislation.