A previously undisclosed report by staffers at the Federal Trade Commission reveals new details about how Google Inc. manipulated search results to favor its own services over rivals’, even when they weren’t most relevant for users.

In a lengthy investigation, staffers in the FTC’s bureau of competition found evidence that Google boosted its own services for shopping, travel and local businesses by altering its ranking criteria and “scraping” content from other sites. It also deliberately demoted rivals.

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