Matt Cutts, a principal search engineer, said Google had learned from the Buzz outcry.
Google introduced its latest social tool on Wednesday, the same day it settled with the Federal Trade Commission over charges of deceptive privacy practices last year for Buzz, the social networking tool in Gmail.
Under the settlement, Google agreed to start a privacy program, permit audits for 20 years and face $16,000 fines for any future privacy misrepresentations. This is the first time the F.T.C. has charged a company with such violations and ordered it to start a privacy program, the commission said.
The new social networking tool, called +1, lets people annotate Google search results and ads so they can recommend Web pages to friends and acquaintances. It is the biggest feature yet in Google’s long-awaited social networking toolkit.
The introduction of +1 and the F.T.C. charges highlight two of Google’s biggest challenges: heightened competition from Facebook, and near-constant criticism from privacy advocates and policy makers over its practices.
As it tries to make its services more social, the company has come under intense scrutiny from people concerned about its broad access to personal information. But at the same time, it is in the unusual position of racing to catch up with a rival, as Facebook captures more of the time, information and ad views of Internet users.
Of particular concern to Google is the fact that many people now turn to Facebook with search queries, like seeking the best place to go on vacation, because they trust the advice of friends more than that of an anonymous search engine.
With +1, which began rolling out to users Wednesday, Google wants to personalize search results.
In an interview about the new tool, Matt Cutts, a principal search engineer at Google, took great pains to emphasize that the company had learned from the privacy outcry after it introduced Buzz, which let Gmail users share status updates, photos and videos.
The debut of Buzz in February 2010 unleashed a barrage of criticism from users and privacy advocates because it automatically included users’ e-mail contacts in their social network.
Mr. Cutts repeatedly stressed that anything people shared with +1 was public.
“If you wouldn’t feel comfortable telling your friends and broadcasting this to the world, then of course you don’t have to click the +1 button,” he said.
Still, some privacy advocates were wary.
“It’s ironic it’s coming out on the same day” as the F.T.C. settlement, said John M. Simpson, an advocate at Consumer Watchdog, a critic of Google. “It seems to me there are some of the same kinds of issues that happened with Buzz. The key is how transparent and open it is about what’s going to be shared and how you share it.”
The name +1 came from Internet slang that people use to indicate that they approve of what someone has said.
People logged into their Google accounts will be able to click a +1 button next to search results to publicly recommend the pages. People perusing results will see how many Google users recommended a page and see names and photographs of people they know. Google is considering whether to use the recommendations to influence the order of search results.
Google will find people that users know through Gmail and chat contacts, as well as people users follow on Google Reader or Buzz. Later it will include contacts from other social sites like Twitter and Flickr. But it will not include contacts from Facebook, because that information is not publicly shared on the Web, Mr. Cutts said. Google has been in a tussle with Facebook over sharing information between the two services.
People will also be able to recommend ads. And if someone recommends a search result that links to a hotel’s Web site and the hotel later advertises on Google, that person’s recommendation will appear with the ad.
“That’s going to be very powerful,” said Bryan Wiener, chief executive of 360i, a digital advertising agency. “A friend’s recommendation is going to have greater influence on consumer behavior than a marketer’s message.” He said it could also lower the cost of ads because Google charges less for ads that are clicked on more.
Google’s +1 is remarkably similar to Facebook’s Like button, which lets people recommend Web sites and ads to their friends.
Later, Web publishers will be able to include a +1 button on their pages, just as many include a Facebook Like button today.