Microsoft today is launching its adCenter online advertising system in the U.S., and will now compete directly with Google and Yahoo! in selling ads on the Web.

The official announcement is coming this morning when Chief Executive Steve Ballmer addresses the company's Strategic Account Summit, a wide-ranging two-day event that on Wednesday included an unusual onstage interview of Chairman Bill Gates that touched on his private and professional life.

Over the past year, Microsoft has been slowly weaning itself from Yahoo!, a rival that it had hired to serve advertising alongside the Redmond company's Web search results. Now, Microsoft will be working directly with advertisers.

AdCenter will give advertisers sophisticated information about consumers, including their location, age, gender and sometimes, their level of wealth. That's more than what Google and Yahoo! offer, said Joe Doran, senior director for monetization in Microsoft's MSN ad-planning group.

The service will also allow advertisers to choose specific times of the day or week in which their ads would be displayed.

"It's a clear differentiation for us," he said. AdCenter will not give any information that can allow advertisers to personally identify a person, he added.

Microsoft earlier launched adCenter in Singapore and France, and for the past nine months it has run a pilot program in the U.S. with 6,000 customers.

The company will begin a similar pilot in the U.K. next month, Doran said.

Search isn't the only place where adCenter will place advertising. In the future, Microsoft said, it expects to launch ads in e-mail, the Spaces blogging program, on mobile applications, in Office and on the Xbox.com Web site.

Gates took the stage at the summit Wednesday for an interview with television talk-show host Donny Deutsch, and answered questions such as what keeps him up at night and what makes him angry.

Being the world's richest man isn't as great as you'd think, he said.

"There's nothing good that comes out of that," Gates said in the interview, which was taped for a future show. When Deutsch suggested that he really wouldn't want to be No. 2 on the list, Gates disagreed.

"No," he said. "You get more visibility as a result of that."

When asked what keeps him up at night, Gates said it's thinking about where Microsoft should be investing.

"What are the breakthroughs we ought to be doing now that will put us in the lead in the future?" he said. "That's the main thing to worry about."

Gates and Deutsch wore lavender shirts, and Deutsch joked that the audience obviously didn't receive the lavender-shirt memo.

One of the toughest questions for Gates to answer was about feeling angry.

"What pisses you off?" Deutsch asked Gates. "I know with $50 billion it's hard to be pissed off, but what does piss you off?"

Gates started to talk about things he gets concerned about, but when pressed for a stronger answer, he paused for several seconds and eventually said: "Not much."

And as in many interviews Gates does these days, the conversation eventually turned to Google. Gates said that the company has done a great job on search and advertising, and that the rivalry is a rare case where Microsoft is actually being underestimated.

"We will keep them honest in the sense of being able to do better on those things, bring a new angle to it," he said. "The intense competition in this business is what makes it fun."

Kim Peterson: 206-464-2360 or kpeterson@seattletimes.com