By MICHAEL LIEDTKE

SAN FRANCISCO (AP) — Google Inc.’s long-anticipated acquisition of online ad service DoubleClick Inc. is expected to turn the Internet search leader into an even more powerful marketing vehicle that’s fueled by better insights about consumers.

The $3.1 billion deal, completed Tuesday after nearly a year of regulatory wrangling, also may intensify the pressure on Microsoft Corp. and Yahoo Inc. to resolve their stormy courtship so they don’t risk further distractions while Google tries to sprint further ahead in the race for Internet advertising.

Google took control of DoubleClick a few hours after Europe’s antitrust regulators removed the final stumbling block by approving a deal that was first announced 11 months ago.

U.S. regulators cleared the transaction in December, casting aside objections from Microsoft and other companies that argued DoubleClick would give Google too much control over online advertising and potentially sensitive information about consumer behavior on the Internet.

Besides opening up new opportunities, Google’s takeover of DoubleClick will create more challenges for a management team already grappling with concerns about how the slowing U.S. economy will affect the company’s earnings growth this year.

Google Chairman Eric Schmidt acknowledged in a statement that the biggest acquisition in the company’s 9 1/2-year history probably will trigger an unspecified number of layoffs after years of relentless hiring. The looming job cuts will be concentrated in the United States, although Schmidt said offices in other countries could be affected.

New York-based DoubleClick has 1,500 employees with offices in France, England, Germany, Ireland, Spain, Australia and Spain. Mountain View-based Google employs nearly 17,000 workers, up from 1,600 just four years ago.

Google’s recently slumping shares soared with the rest of the stock market Tuesday, gaining $26.22, or 6.3 percent, to $439.84. The company’s stock price remains down by 36 percent so far this year.

DoubleClick is expected to broaden Google’s already extensive reach in the $40 billion Internet advertising market.

Google has been the market’s most dominant player so far, generating more than $16 billion in revenue last year. Most of the money flowed in from short, written ads that Google places alongside search results and other Web content.

DoubleClick specializes in placing more dynamic, multimedia ads, a form of marketing that is expected to become more important in the next few years as big companies spend more money promoting their brands online.

With somewhere between $300 million and $400 million in annual revenue, DoubleClick isn’t expected to have a significant impact on Google’s profit this year.

But the addition is bound to give Google an important advantage over its rivals, said Russ Mann, chief executive of Covario, which helps manage and analyze online advertising campaigns.

“Google is going to be like a runaway locomotive coming full steam ahead now,” Mann said.

Standard & Poor’s equity analyst Scott Kessler isn’t convinced the deal will pay off for Google as quickly as some might think, largely because the company doesn’t have a track record of mining big profits from its past acquisitions. For instance, Google paid $1.76 billion for online video leader YouTube in November 2006, but the site still isn’t producing significant profits.

“It’s definitely a big deal, but whether they can execute on the potential remains to be seen,” Kessler said.

But just the prospect of Google growing even stronger now that DoubleClick is in its fold could be enough to prompt Microsoft to step up its pursuit of Yahoo or withdraw its offer to spend the money on other expansion opportunities.

“Everyone knew the (DoubleClick) deal was coming, but (the consummation) probably contributes a degree of urgency because now it is real,” Kessler said.

Microsoft has offered to buy Yahoo for more than $40 billion, but the unsolicited bid has been at a standstill for the past month because the two sides can’t agree on a price.

Both Microsoft and Yahoo had opposed Google’s acquisition of DoubleClick, arguing that it could stifle competition in the online advertising market and potentially compromise consumer privacy.

Representatives of both Microsoft and Yahoo declined to comment Tuesday.

Google’s pursuit of DoubleClick had a domino effect almost as soon as the two companies announced their marriage plans last April. Within a few months, Microsoft, Yahoo and Time Warner Inc.’s AOL had spent more than $7 billion snapping up other online ad networks and tools to mount a counterattack.

Besides helping Google build a one-step shop for advertisers and Web publishers, DoubleClick also brings a wealth of information about consumer behavior accumulated through years of tracking online surfing.

Coupled with the knowledge Google has gleaned from analyzing its users’ search requests, DoubleClick’s data will provide an even better understanding about what appeals to each individual consumer.

Google, which has embraced “don’t be evil” as its motto, has pledged to vigilantly guard the information. Management believes the data will lead to more relevant and less annoying ads, making the Internet more enjoyable.

“We will be able to help publishers and advertisers generate more revenue,” Schmidt wrote. “That in turn will fuel the creation of even more rich and diverse content for Internet users everywhere.”

But consumer watchdogs are worried about too much power — and information — being concentrated at a single company.

The Center for Digital Democracy, a privacy advocate, said regulators’ failure to impose safeguards had “helped strengthen a growing digital colossus that will now be in a dominant position to shape much of the global future of the Internet.”

PHOENIX -(Dow Jones)- Microsoft Corp.’s (MSFT) top advertising executive said Monday that an Internet advertising industry duopoly formed through a combination with Yahoo Inc. (YHOO) would be preferable to allowing one company to establish a monopoly in the sector.

“A duopoly is better than a monopoly,” said

McAndrews never specifically referred to rival Google Inc. (GOOG) as the monopoly in question, but he told an audience at the Interactive Advertising Bureau conference in Phoenix that only Microsoft and Google had the resources to develop the massive online advertising platforms for the future.

Microsoft has argued that taking over Yahoo would be the quickest way for the software giant to close the gap with Internet search and advertising giant Google. The global Internet advertising market is expected to grow from $45 billion in 2007 to $147 billion in 2012, at which time online ads will account for 21% of overall advertising budgets, the Kelsey Group said Monday.

McAndrews made his duopoly comment in response to advertisers’ concerns that they would have fewer options for placing Internet ads should Microsoft succeed with its $41.2 billion bear hug for Yahoo.

One digital advertising executive with a major U.S. corporation told Dow Jones that the combination of Microsoft and Yahoo would mean his company could no longer play the two off each other to secure better ad rates.

McAndrews, the former chief executive at aQuantive, an Internet advertising group recently bought by Microsoft, also said his company would soon start testing new technology that could change the way advertisers measure the effectiveness of their ads. The new technology is designed to improve Internet advertising accountability at a time that advertisers are demanding better data about who is seeing their ads and how those users are responding to them.

The current system ties traffic, leads and sales to the last ad that users see before engaging in an online transaction. But McAndrews said the current system is outdated and flawed because it does not take into account all the other ads that consumers have seen - across many Web sites - that helped influence their buying decision.

The new technology will track the frequency that consumers see ads and identify the most recent ads they saw, as well as factor in ad format and size, McAndrews said. Groups such as Citi Cards and Best Western International Inc. have signed on for the trial, he said.