Launched in February 2010 to compete with Twitter, Buzz initially used its Gmail customers' email contact lists to create social networks of Buzz contacts the rest of the world could see, which led to an uproar.
Google quickly changed the settings so that contacts were kept private by default. It settled with the FTC on Buzz in March 2011.
Google has said the tracking of Safari users was inadvertent and that it collected no personal information such as names, addresses or credit card data. But the tracking was done despite assurances Safari could be set to protect user privacy.
The company said the investigation was prompted by a 2009 help center Web page that predated a change in Apple's cookie-handling policy.
"We have now changed that page and taken steps to remove the ad cookies, which collected no personal information, from Apple's browsers," a Google spokesperson said on Thursday.
The Safari issue was not Google's first brush with potential privacy violations.
It tightened its privacy policy in the wake of revelations that Street View cars, which take panoramic pictures of city streets, inadvertently collected data from unsecured wireless networks in more than 30 countries.
The FTC has closed its investigation into the issue, which was also probed by the governments of Britain, France, Singapore and Switzerland, among others.
Vladeck said Google's repeated defense that privacy blunders were inadvertent was troubling to the agency and raised red flags for regulators.
"A company like Google that is the steward of personal information from hundreds of millions of people has to do better," he said.
