Dear Dr. Don,
I would like to know how consumers should go about closing "open accounts," especially if one now has multiple accounts due to banks buying out other banks or creditors.

Recently, I've read on Bankrate.com that closing accounts can lower your credit score. How should one handle these unused accounts? Is there a magic number as to how many to close per month or year without gravely affecting one's good credit score?
-- Marie Multiple

Dear Marie,
A balancing act is involved when deciding whether to hold on to accounts you don't use (just to keep your credit score high) or to close those unused accounts.

Keeping the accounts open helps maintain a low ratio between outstanding balances and available credit lines -- that's called the credit utilization ratio. Not bumping up against your credit limits shows you're not running out of available credit. Lenders like borrowers who aren't desperate.

The length of time the account has been open also influences your credit score. Having a clean payment history on an account with a 10-year history is more valuable to your credit score than a clean payment

HOUSTON (AP) -- Suppose Exxon Mobil decided to return the favor and buy you a tank of gas. Then again, why stop there? The oil giant turned a profit last year fat enough to buy a fill-up for every car, truck and SUV in America -- four times.

Beating its own record to rack up the largest annual corporate profit in American history, Exxon Mobil Corp. said Friday it earned $40.6 billion for the year, reaping the benefits of crude-oil prices around $100 a barrel.

Exxon Mobil also topped its own record for profit in a single quarter, posting net income of $11.7 billion for the final three months of the year -- about $1 billion more than the same period in 2005, the previous quarterly record.

The annual profit was enough, at $3 a gallon, to buy nearly four 15-gallon fill-ups for the roughly 243 million registered passenger vehicles on American roads. Put another way, it's almost equal to what Microsoft has offered to buy Yahoo outright.

And the quarterly profit alone is about the same as the size of the entire economy of Iceland or Namibia. The previous record for annual profit was $39.5 billion, posted by Exxon Mobil in 2006.

Chevron Corp., No. 2 behind Exxon Mobil among U.S. oil companies, also had its best year ever in 2007

SAN FRANCISCO (AP) -- Unable to topple Google Inc. on its own, Microsoft Corp. is trying to force crippled rival Yahoo Inc. into a shotgun marriage, betting nearly $42 billion that the two companies together will have a better chance of tackling the Internet search leader.

Microsoft's audacious attempt to buy Yahoo, spelled out in an unsolicited offer announced Friday, shows just how much Google threatens the world's largest software maker's grip on how people interact with computers.

For Yahoo, the bid represents another painful reminder of how missed opportunities and mismanagement combined to open the door for Google to supplant it as the Internet's main gateway, decimating its stock price in the process.

Redmond, Wash.-based Microsoft is trying to avoid a similar fate at Google's hands as more people access services and computer programs online instead of relying on packaged software applications.

Although Microsoft remains the world's most valuable technology company, its position will become more precarious unless it can cultivate a more loyal Internet audience and generate more online ad revenue to subsidize the free services taken for granted on the Internet.

Microsoft is acutely aware of the upheaval that can be caused by a pivotal shift in technology, having

CINCINNATI (AP) -- The nation's biggest advertiser is running some options for the nation's biggest football game.

Procter & Gamble Co., with a nearly $8 billion global annual advertising budget, has already aimed some brand promotions, using celebrities, online sites and contests, at football fans and families as the Super Bowl approaches on Sunday. But Tide detergent is going for the big play.

The six-decade-old brand has bought its first Super Bowl commercial, one of the 30-second ads on the Fox television network estimated to be going for some $2.7 million this year. It will feature Tide to Go, a cleaning pen that moved Tide beyond the laundry room in 2005.

Making the call on whether to pay big bucks for Super Bowl TV time or use their budget on other outlets is one of the key huddles that marketing teams can have each year. It's a national must-see event, with over 90 million men, women and children of all ages and demographics gathered in front of their TV sets.

And best of all for advertisers in this age of media fragmentation and digital video recorders fast-forwarding through commercials, the ads are part of the viewing fun.

"People look forward to the commercials," said Gary Stibel, who heads the New England Consulting Group

TOKYO (AP) -- Nissan reported a 26.6 percent jump in October-December profit Friday and kept its full year forecasts despite looming worries about a U.S. slowdown and an unfavorably strong yen.

Profit at Nissan Motor Co., which has an alliance with Renault SA of France, rose to 132.22 billion yen ($1.24 billion) for the fiscal third quarter from 104.46 billion yen the same period the previous year.

Quarterly sales climbed 18.2 percent to 2.770 trillion yen ($26.03 billion) from 2.343 trillion yen, partly boosted by brisk sales of the Rogue crossover vehicle in the U.S.

Earnings at Japan's No. 3 automaker, which also makes the Z sportscar, Altima coupe and Infiniti luxury models, could be endangered in coming months amid worries about slower American consumer spending.

Also, a weaker dollar, which has dropped recently to about 106 yen from 114 yen last year, eats into the revenue from U.S. exports for the Japanese.

But so far demand for Nissan vehicles has remained strong in the U.S. and in emerging markets such as the Middle East, China and Russia. Even in the domestic Japanese market, the company boosted its market share, it said.

"Despite the headwinds that affect our industry, Nissan has benefited from the success of the new products launched during the past 12 months," said Nissan Chief Executive Carlos Ghosn, who also heads