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.”

By MICHAEL LIEDTKE

Facebook Inc. has raided Google Inc. to hire a new chief operating officer, providing the popular online social network with more seasoned management and advertising savvy as it strives to make more money without alienating its audience.

Sheryl Sandberg’s defection from Google, announced Tuesday, represents a coup for Facebook just three months after it suffered a humiliating setback in its effort to inject more commercialism into its fun-loving Web site.

As Google’s vice president of global online sales and operations for the past six years, Sandberg helped build the Internet search leader into one of the world’s most prized companies. She also helped set up Google.org, the Mountain View-based company’s philanthropic arm.

Before joining Google, she served as the U.S. Treasury Department’s chief of staff during the Clinton administration.

With Sandberg’s hiring, effective March 24, Facebook fills a void created last summer when it reassigned its previous chief operating officer, Owen Van Natta, to chief revenue officer. Van Natta left Facebook last month.

Besides helping steer Facebook’s expansion, Sandberg, 38, could serve as a mentor for the Palo Alto-based company’s 23-year-old founder and chief executive, Mark Zuckerberg, to whom she will report directly.

Sandberg said in an interview that she is just one of several veteran executives who can act as a sounding board for Zuckerberg. She also pointed to Gideon Yu, who became Facebook’s chief financial officer in July after stints with Yahoo Inc., Google’s YouTube and a venture capital firm.

“Mark is inspiring,” Sandberg said. “He has more clarity and vision than just about anyone I ever met.”

In an interview, Zuckerberg said he is counting on Sandberg to minimize Facebook’s growth pains.

“Anyone who has ever worked with her raves about how she helped make them better managers,” he said. “She has a terrific track record.”

Sandberg’s departure from Google comes amid widening fears on Wall Street that the advertising sales propelling Google’s growth are bound to slow as the U.S. economy flirts with a recession.

Worries about a general economic slowdown are the main reason Google’s market value has plunged about 35 percent, or $75 billion, already this year.

Google shares dropped to a new 52-week low of $435.78 Tuesday before bouncing back to close at $444.60, down $12.42.

“I am certainly not leaving Google because there is anything wrong there,” Sandberg said. “I think Google’s best days are still ahead.”

She said she simply couldn’t turn down the chance to help Facebook shape the social networking craze that has swept up millions of teenagers and young adults.

Facebook’s audience has more than tripled in the past 11 months to 66 million users, making it the second largest social network behind News Corp.’s MySpace.com.

With 500 employees and more than $100 million in annual revenue, Facebook is far smaller than Google, which has nearly 17,000 employees and more than $16 billion in annual revenue after less than a decade in business. Facebook hopes to double its payroll to 1,000 employees by the end of this year, Zuckerberg said.

Facebook’s rapid rise since its inception four years ago has caused some analysts to wonder if the startup could blossom into the Internet’s biggest success since Google went public in August 2004.

Having already rebuffed a chance to sell Facebook to Yahoo Inc. for $1 billion in 2006, Zuckerberg had indicated he hopes to take his company public in 2009 or 2010.

Microsoft Corp. stoked the exuberance about Facebook late last year by paying $240 million for a 1.6 percent stake that valued the privately held company at $15 billion.

But Facebook stumbled badly shortly after winning Microsoft’s stamp of approval by rolling out a new advertising system that infuriated thousands of its users and raised questions about Zuckerberg’s judgment.

The marketing tool, called “Beacon,” tracked Facebook’s users’ purchases and actions at dozens of Web sites and then broadcast the data on the pages of their listed friends within its social network. After days of protests, Zuckerberg finally apologized and made it easier for Facebook users to block Beacon.