It mostly affects the one in four people who log into Google or Google+ while searching the Web. Those users will have the option of seeing search results that are customized to their interests and connections, say, a photo of the family dog or a friend's recommendation for a restaurant.
A privacy watchdog group probably will complain to the U.S. Federal Trade Commission that a new Google search feature raises privacy and antitrust concerns.
Marc Rotenberg, executive director of the Electronic Privacy Information Center, said his group is considering filing a letter with the FTC.
EPIC made the complaint that resulted in Google's settlement with the FTC that requires the Internet search giant to submit to external audits of their privacy practices every other year.
"We believe this is something that the FTC needs to look at," Rotenberg said.
Google calls the new feature rolling out to users of its English-language search engine "Search Plus Your World." It blends information such as photos, comments and news posted on its Google+ social network into users' search results.