REDMOND, Wash. (Reuters) - Microsoft Corp. Chairman Bill Gates said Wednesday he wished he were not the world's richest man.

"I wish I wasn't. There is nothing good that comes out of that," said Gates, whose personal fortune sank by billions since last week when the software giant disappointed investors by saying new investments would crimp earnings.

Microsoft Chairman Bill Gates

The corporate leader who made Microsoft into the world's largest software maker - and who is also one of the biggest philanthropists - is seen as a man who does not like publicity. He explained that he did not like the attention of being the world's richest person.

"You get more visibility as a result of it," he said during an interview conducted by CNBC reporter Donny Deutsch in front of a crowd of people attending a Microsoft advertising event. (Watch Bill Gates on CNN Pipeline's CNNMoney Business Update - 1:54)

The Microsoft co-founder said that the person he learned most from in the world, aside from technology colleagues, was fellow-billionaire and legendary investor Warren Buffett.

"He has this very refreshing, simple way of looking at things so I put him top of the list," said Gates, adding that the top lesson from Buffett was the importance of integrity.

Still, Gates joked about his plight being unequaled in wealth. Asked if he surrounded himself with financial peers, he quipped, "No, I sit alone."

Gates has been the richest man in the world for eight years running - since 1998 - and was worth $90 billion at his fortune's peak in 1999, according to the Forbes list of richest people. His fortune is currently at $50 billion, according to the magazine.

SEATTLE (Reuters) - Microsoft said Wednesday it switched to its own online ad brokering service called adCenter, so advertisers can directly place ads on the software maker's search sites instead of going through Yahoo.

Microsoft's launch of adCenter is part of the world's largest software maker's push to better compete with Internet rivals Google (Research) and Yahoo (Research) in a U.S. online advertising market estimated to be worth around $15 billion.

Microsoft makes bid to take a bigger piece of a U.S. online advertising market estimated to be worth around $15 billion.

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After relinquishing the early advantage in paid search, Microsoft (Research) has invested heavily in recent years to create its own search engine and ad brokering service.

Advertisers bought pay-per-click ads on MSN search through Yahoo's Overture service until last year, but adCenter handled an increasing percentage of those transactions during testing in recent months.

In order to lure more advertisers to adCenter, Microsoft aims to increase the number of people using its search site.

The company started testing a new Windows Live search engine with features aimed at allowing users to more simply view search results. However, its main MSN search engine lost market share again to Google and Yahoo in March.

Its U.S. share fell to 11 percent from 14 percent, while Google and Yahoo each gained, rising to 49 percent and 22 percent of the search market.

AdCenter will be initially limited to paid search, but Microsoft envisions the service being a one-stop shop for online advertising across many of the company's software platforms including Xbox games and mobile phones.

The brokering service is expected to eventually allow advertisers to place advertisements on Microsoft's Internet services sites, such as Windows Live e-mail or Office Live.

Analysts forecast Microsoft will spend an additional $2 billion in the coming fiscal year starting July 1, speculating that much of the investment will go toward building an infrastructure for an online services supported by ad revenue.

"The ad community is extremely important to us as we evolve Microsoft from a software company into the world's largest, most attractive provider of online media through MSN, Windows Live and adCenter," Microsoft Chief Executive Steve Ballmer said in a statement.

Microsoft said adCenter allows advertisers to better track spending campaigns while providing more data to target potential customers.

The brokering service runs in the U.S., France and Singapore with tests starting in June in the UK.

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NEW YORK (CNNMoney.com) - Amazon.com has dropped Google as its search provider in favor of Microsoft, an important victory for the Seattle software maker as its battle with the 400-pound gorilla of search heats up, according to a report Tuesday.

Searches on Amazon.com are now powered by Windows Live Search, Microsoft's new search engine that's still in the testing phase, the Washington Post said Tuesday.

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"Our engineers have done some testing and evaluation, and overall we concluded this was an interesting option to discover information," Amazon executive David Tennenhouse told the newspaper.

The news is significant for Microsoft (Research) because moves by Amazon (Research), one of the world's largest Web-based retailers, are closely watched by other Internet shopping sites, according to the article.

The battle between Microsoft, the world's largest software company, and Google (Research), the world's largest Internet search provider, is intensifying as Microsoft tries to muscle more Internet market share from the search industry leaders, Google and Yahoo! (Research).

Microsoft recently said it was plowing money into research and development, and Chairman Bill Gates was quoted in a report describing the relationship between his firm and Google as "hypercompetition."

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