Deleting personal information online is costly and time-consuming for Web companies. Those difficulties are now set to be magnified in Europe for Google Inc., Microsoft Corp. and others.

The European Union’s top court Tuesday ruled citizens have a “right to be forgotten” online, meaning people may ask search-engine owners to remove personal information and request that a court or data-protection authority step in if a company doesn’t comply. The EU decision doesn’t spell out what types of information must be removed and doesn’t provide exemptions for data that are true or from a reputable source.

All of that is set to create new headaches for U.S. Web companies, which have businesses based on handling tremendous amounts of data that often aren’t touched by humans. The ruling opens the way for European users to flood the firms with Web takedown requests, adding costs and time to what they already do in content removal. Many of the companies already deal with compliance for different data laws in various geographies, subjecting requests to shed content to thorough legal analyses before making the information unavailable. 

“It’s just such a mind-bogglingly impossible decision,” said Fred Cate, distinguished professor at the Indiana University Maurer School of Law. “Courts aren’t responsible for the practical implications of rulings but this really staggers the imagination.”

The EU decision is only binding on Google, which was front and center in the case that the Luxembourg-based tribunal ruled on, Cate said. Yet the principles also apply to companies like Microsoft with its Bing search engine and Yahoo! Inc., he said.

Google and others may now have to consider charging a fee for European users to cover the costs of staff to comb through requests, Cate said. Or they may try to get by with being seen to make a good faith effort to comply, even though any of the 28 European nations governed by the ruling or any zealous local prosecutor could then take a company on for failing to do enough, he said.

“They’d have to hire an army of compliance officers,” said Justin Brookman, director of the Center for Democracy and Technology’s Project on Consumer Privacy. That may make it difficult for companies to “scalably compete online,” he said.

The EU decision illustrates how Europe and the U.S. are diverging on how stringently they approach privacy. That has gathered steam since last year, following Edward Snowden’s revelations of the electronic-spying practices of the U.S. National Security Agency.

Google said it was reviewing the EU court’s decision, with spokeswoman Leslie Miller calling it a “disappointing ruling for search engines and online publishers in general.”

Other Internet companies said they have also started studying the ruling and its implications.

“Since our founding almost 20 years ago, we’ve supported an open and free Internet; not one shaded by censorship,” said Sarah Meron, a spokeswoman for Sunnyvale, California-based Yahoo. “We’re now carefully reviewing the European Court of Justice’s decision to assess the impact for our business and for our users.”

Jack Evans, a spokesman for Microsoft, declined to comment. Nu Wexler, a spokesman for Twitter Inc., and Genevieve Grdina, a spokeswoman for Facebook Inc., didn’t respond to requests for comment. (Bloomberg)