Led by the French, organizations in Britain, the Netherlands, Germany, Spain, and Italy agreed Tuesday on the joint action, with the ultimate possibility of imposing fines or restrictions on operations across the entire 27-country European Union.
Last year the company merged 60 separate privacy policies from around the world into one universal procedure. The European organizations complain that the new policy doesn't allow users to figure out which information is kept, how it is combined by Google services, or how long the company retains it.
The fines' financial impact on Google would be limited -- French privacy watchdog CNIL has the right to fine the company up to 300,000 euros ($385,000), approximately the amount it earns in three minutes, based on its projected revenue of $61 billion this year. Britain can fine up to 500,000 pounds, but rarely does.
But successful legal action would hurt Google's image and could block its ability to collect such data until it addresses the regulators' concerns.
Google dominates the European market for Internet searches. According to one survey, as much as 95 percent of searches in Europe are carried out through Google, compared with about 65 percent in the United States. European regulators have demanded specifics for anyone using Google on what's being collected and a simpler presentation.
Tensions between privacy and the swiftly evolving ability of companies to spin online usage data into vast profits are ramping up, especially in Europe where privacy laws tend to be strong and nearly every country has a regulatory body. But Internet users have consistently shown a willingness to give up privacy in exchange for convenience and new online services that Google and other tech companies offer.
Google says it merged its myriad privacy policies in March 2012 for the sake of simplicity, and that the changes comply with European laws.
"There is a wider debate going on about personal data and who owns and controls personal data," said Colin Strong, a technology analyst with GfK. "The question is the extent to which consumers understand the value of their personal data and the extent that they are happy with the trade that they're getting."
Google has not commented publicly on the process, beyond saying that it complies with European law.
"No one is against Google's objective of simplicity. It's legitimate. But it needs to be accompanied by transparence for consumers and the ability to say yes or no," Isabelle Falque Pierrotin, head of French privacy regulator CNIL, said in a recent interview. "Consumers have the right to know how the information is being used and what's being done with it."
Each of the six European states bringing legal action against Google has to make its own decision on how to handle perceived violations.
But regulations tend to lag technology, analysts say, and the delay is more pronounced in a digital age when small bits of information can offer increasingly powerful insights into the psyches of consumers or voters.
"Technology takes two steps forward and law, if we're lucky, can take them one step back," said Anthony Mullen, an analyst with Forrester Research who advises companies on emerging technologies.