Update: Google revealed in a blog post today that it received formal notification from the FTC yesterday "that it has begun a review of our business."
Google stated its unclear what the FTC's focus is and Google will cooperate with the probe.
The original post follows:
Remember that little U.S. Department of Justice probe of Google's then-pending ITA Software acquisition?
It could be small potatoes compared with the U.S. Federal Trade Commision's Google probe, which reportedly is getting into gear.
The Wall Street Journal reported today that the FTC is readying subpoenas of Google, "signaling the start of a wide-ranging, formal antitrust investigation into whether the search giant has abused its dominance on the Web."
The story punctuates the fact that the FTC probe isn't a run-of-the mill antitrust investigation of a Google acquisition. The article states:

The new FTC investigation, by contrast, will examine fundamental issues relating to Google's core search advertising business, which still accounts for the overwhelming majority of its revenues. Those will include whether Google -- which accounts for around two-thirds of Internet searches in the U.S. and more abroad -- unfairly channels users to its own growing network of services at the expense of rivals'.
A Google spokesman declined to comment about the FTC probe and The Wall Street Journal story.
Assuredly Google Places and aspects of the search engine's hotel advertising business would come under the microscope.
In fact, Henry Harteveldt, principal travel analyst at Forrester Research, offers that he "expects the probe will examine how Google’s placement and presentation of its proprietary tools and content, like Google Places, has been used for travel-related searches."
Speaking at the Nasdaq OMX 26th Investor Program in London this week, Dara Khosrowshahi, Expedia Inc.'s president and CEO, noted that its TripAdvisor unit took a traffic hit when its results were pushed lower in Google Places, although the impact from the latest iteration of Google Places was less severe, although still a negative.
And, of course there is considerable concern from some quarters in the travel industry about what Google is up to in airfare search with ITA Software and hotel advertising, too.
FairSearch.org, the coalition that fought Google's acquisition of ITA Software, issued a statement about the FTC probe:

The members of FairSearch.org are encouraged by reports that the FTC is preparing to launch a broad antitrust investigation into Google’s business practices. Google engages in anti-competitive behavior across many vertical categories of search that harms consumers by restricting the ability of other companies to compete to put the best products and services in front of Internet users, who should be allowed to pick winners and losers online, not Google.
The result of Google’s anti-competitive practices is to curb innovation and investment in new technologies by other companies. These anti-competitive practices include scraping and using other companies’ content without their permission, deceptive display of search results, manipulation of search results to favor Google’s products, and the acquisition of competitive threats to Google’s dominance. Google’s practices are deserving of full-scale investigations by U.S. antitrust authorities, and are already the subject of reviews by the European Commission, and the Texas Attorney General.