Nazi paraphernalia and certain hate speech in Germany and France.
The company has also set up a process so people can have their images blurred if they appear in Google's street-level photographic maps.
But Google and other such companies rely heavily on formulas, or algorithms, and automated "crawlers'' that roam the Internet and gather up results in response to search requests.
What they have sought to avoid is acting as the arbiters of what kind of information to include in their searches.
"There's not much guidance for Google on how to figure out how and when they are supposed to comply with take-down requests - they just know they have to weigh the public interest,'' said Joel Reidenberg, a Fordham University law professor now visiting Princeton University.
The case was referred to the European Court from Spain's National Court, and involved Mario Costeja, a Spaniard who found a search of his name turned up links to a notice that his property was due to be auctioned because of an unpaid welfare debt. The notice had been published in a Spanish newspaper in 1998, and was tracked by Google's robots when the newspaper digitized its archive.
Costeja argued that the debt had long since been settled, and he asked Spain's privacy agency to have the reference removed. In 2010, the agency agreed, but Google refused and took the matter to court, saying it should not be asked to censor material that had been legally published by the newspaper.
"It's a great relief to be shown that you were right when you have fought for your ideas. It's a joy,'' Costeja said.
“He said that "ordinary people will know where they have to go'' to complain about bad or old information that turns up on a Google search.
Costeja's case will now return to Spain for final judgment. There are about 200 others in the Spanish court system, some of which may still prove difficult to decide. For instance, one involves a plastic surgeon who wants mentions of a botched operation removed from Google's results.
Debates over the "right to be forgotten'' have surfaced across the world as tech users struggle to reconcile the forgive-and-forget nature of human relations with the unforgiving permanence of the Internet.
Though the idea of such a right has generally been well-received in Europe, many in the U.S. have criticized it as a disguised form of censorship that could, for example, allow ex-convicts to delete references