Facebook's newest tools application, which allows users to see personalized versions of websites they visit elsewhere, is the latest change to the social networking site that is raising privacy concerns.

The "Instant Personalization" application allows users to see websites tailored to them based on their interests and social connections, as long as they are logged into Facebook.

The initial sites involved in the application are Yelp, Pandora and Microsoft Docs.

More are expected to join, Facebook said.

Facebook CEO Mark Zuckerberg told developers at Wednesday's launch at a conference for web and software developers in San Francisco that the application will mean a more personalized, social, smarter web.

But internet analysts and Facebook users said the program violates their privacy.

Opting out possible

User after user has posted warnings on Facebook accounts about "Instant Personalization," calling it an invasion of privacy, and listing steps on how to opt out of the program, as all Facebook users are automatically signed into it by default.

"As of today, Facebook has a new privacy setting called 'Instant Personalization' that shares data with non-Facebook websites and it is automatically set to 'Allow.' Go to Account > Privacy Settings > Applications and Websites, and uncheck 'Allow,' then repost this to your profile," is the common warning.

"How many people are really going to want all this information about them shared?" said Greg Sterling, an internet analyst who also writes for SearchEngineLand.com. "That's the big unanswered question here."

Sharon Machlis, online managing editor of ComputerWorld.com said users should have been warned that they would start seeing Facebook requests showing up when they visit other sites, even before they've logged into those sites.

"It's a safe bet this won't be the last time Facebook decides to troll through my data and come up with new ways of sharing," Machlis wrote Friday in her blog, Machlis Musings.

"I'm not sure I can trust them to understand that just because I'm using Facebook doesn't mean I want in on every partnership they make."

Privacy concerns not new

In 2007, Facebook's Beacon tool caught users off-guard as their activities at other websites got broadcast on the networking site, alerting friends, for instance, of holiday gifts just bought for them.

Facebook later gave users the option to turn it off before the company killed the program.

This time, though, Zuckerberg said Facebook made sure that its new tools don't intrude on privacy. Users' preferences won't be logged unless they choose to press the "like" button on websites.

If anything, Zuckerberg expects the "like" tools to give people more control over what they want to share with their online entourages.

With files from The Associated Press