Google maintains that the ruling contradicted a European Union directive on electronic commerce that gives service providers safe harbor from liability for the content they host.

But prosecutors argued that because Google handled user data — and used content to generate advertising revenue — it was a content provider, not a service provider, and therefore broke Italian privacy law. It prohibits the use of someone’s personal data with the intent of harming him or making a profit.

“To say this is about censorship has a big media effect, but is false,” said Alfredo Robledo, one of the prosecutors. “This is about finding a balance between free enterprise and the protection of human dignity.”

Still, the upshot of the ruling, if it prevails on appeal, is that Google will be expected in Italy to monitor the content it hosts. Mr. Echikson, the Google spokesman, said that would be impossible considering that 20 hours of video are uploaded to its site every minute.

The American ambassador to Italy, David Thorne, said he was “disappointed” by the ruling.

“We disagree that Internet service providers are responsible prior to posting for the content uploaded by users,” he said in a statement, adding that Secretary of State Hillary Rodham Clinton had said that “free Internet is an integral human right that must be protected in free societies.”

Mr. Robledo said that a company like Google could easily find ways to monitor its content, and that it should not profit from advertising revenue generated from content that violated privacy laws. He said if Google had found a way to create filters in China, it could do the same in Italy, not to monitor political content “but to protect human dignity.”

Google disagreed.

“If company employees like me can be held criminally liable for any video on a hosting platform, when they had absolutely nothing to do with the video in question, then our liability is unlimited,” said one of the three executives, Mr. Fleischer.