What mattered most to both Google users and competitors was Google’s search practices, which had never been put under the regulatory microscope to such a degree and which the F.T.C. left untouched.

Google’s search results have evolved significantly from its early, simpler days. When I searched for “flight JFK to LAX” this week, I got three categories of results: paid ads at the top and on the right; a Google-produced chart comparing flight options with the disclaimer, which you need to click on, that “Google may be compensated by these providers”; and so-called organic results below that. The first two organic results were entries for Expedia, a rival to Google’s travel site. But given the layout and size of my screen, none of the organic results were visible unless I scrolled down.

However clearly labeled, the prominence of Google’s own travel results gives pause to some antitrust experts. “Location is important,” Professor Picker said. “No one thinks otherwise. Years ago, it was important for airlines’ reservations systems to be on the first screen. But I’m not sure this is an antitrust problem.”

Still, the issue is likely to be a focus of the European Union’s investigation of Google, and it will probably be less sympathetic to unbridled competition on the Internet than the American authorities, and more inclined to protect competitors.

My flight search results seem to bear out the finding that Google doesn’t manipulate organic results, and the paid ads were clearly labeled. But what about the chart Google put together, the result of its 2011 acquisition of the travel site ITA Software? It’s certainly useful to anyone planning to book a flight, and it’s easy to use. It’s information I’d like to see as a consumer. But does it eliminate the need to go to Expedia, leveraging Google’s dominant position in search to harm a competitor? And given that the results in the box may reflect payments to Google, is the information objective?

Or try some shopping options, like “Nike shoes.”

On the top right — the first thing my eyes hit upon — was a box put together by Google, with pictures of Nike shoes and prices from various retailers. The organic results featured several Nike entries and various shoe retailers, but no comparison shopping sites, at least not on the first page. Google discloses that the retailers in the box, too, may have made payments to Google.