SAN FRANCISCO — Microsoft is trying to skewer Google as a lousy holiday shopping guide in its latest attempt to divert more traffic to its Bing search engine.
The attack started Wednesday with a marketing campaign focused on a recent change in the way Google operates the part of its search engine devoted to shopping results. The revisions require merchants to pay Google to have their products listed in the shopping section.
In its new ads, Microsoft contends the new approach betrays Google's long-standing commitment to provide the most trustworthy results on the Web, even if it means forgoing revenue. To punctuate its point, Microsoft is warning consumers that they risk getting "scroogled" if they rely on Google's shopping search service.
The message will be highlighted in TV commercials scheduled to run on NBC and CNN and in newspaper ads in the New York Times, Wall Street Journal and Washington Post. The blitz also will appear on billboards and online, anchored by a new website, Scroogled.com.
The barbs are injecting more antagonism into an already bitter rivalry between two of the world's best-known and most powerful technology companies.
Google's search engine is dominant on the Internet, while Bing runs a distant second. Microsoft's Office and Windows software remains an integral part of personal computers, but Google has been reducing the importance of those programs and PCs with the success of Web-based services and its Android operating system for smartphones and tablet computers.
Google doesn't require websites to pay to be listed in its main database, the index that provides results for requests entered into its all-purpose search box. A query made there for a particular product, such as a computer, will still include results from merchants who haven't paid for the privilege of being included.
But that's not the case for someone who clicks on a tab to enter Google's shopping-only section, which is designed to compare prices and offer other insights, such as identifying sites that offer free shipping. Searches there are confined to paying merchants. That means results from sites, including Web retailing giant Amazon.com, aren't displayed unless they pay.
Google defends the fee-based approach as a way to encourage merchants to provide more comprehensive and accurate information about what they're selling.
Google, like Microsoft, accepts payments for ads that are triggered by specific search terms and appear to the right or on top of regular search results. Those are labeled in colored letters as ads. The same distinctions aren't made in Google's shopping section.
The financially driven system for determining the results in a major part of Google's search engine breaks new ground for a company whose idealistic founders, Larry Page and Sergey Brin, once railed against the perils of allowing money to influence which Web links to show.
Microsoft contends that Google is doing a disservice to its users with the new approach, as many users may not even realize that the results in shopping searches are being swayed by money.
"We want consumers to know, in contrast to the route that Google has pursued, we are staying true to the DNA of what a good search engine is really about," said Mike Nichols, Bing's chief marketing officer. "We will rank results on what's relevant to you and not based on how much someone might pay us."