Do you want to tell your Facebook friends that you are eating at that fabulous new restaurant in town? Well, now you can. But maybe you should think twice.

In yet another red flag on the Facebook privacy front, privacy advocates have raised concerns over the giant social network's latest product, Places, which has been released in the U.S. and may be available in Canada as early as September.

The new application allows Facebook users to "check in" to real locations like a restaurant or cinema and to "tag" the friends that are with them, similar to tagging friends in photos.

Facebook CEO Mark Zuckerberg, right, talks with employees before announcing the social network site's new localization service called Places on Aug. 18, 2010 in Palo Alto, Calif.(Tony Avelar/Associated Press)

The new feature competes with current location programs such as Google's Latitude, Foursquare, Loopt and Gowalla. But privacy advocates are concerned that it is just another way for marketers or identity thieves to create a more detailed profile of someone's life.

Once you are checked into a location, Facebook creates a story in your Facebook friends' news feeds and posts a notice in the recent activity section of the location page.

The "Here Now" feature lists everyone who has checked into a particular place and users are listed on the site for several hours after they have checked in.

Kurt Opsahl, a senior staff attorney with the San Francisco-based Electronic Frontier Foundation, wrote recently that, "Like all location products, the new application publishes potentially sensitive information and can provide a detailed picture of your life."

It is also compiling data that can be hugely valuable to marketers.

User controls

As Colin Bennett, a political science professor at the University of Victoria, puts it: "People are encouraged on social networking sites to share information about what they are doing and where.

"Geodemographics — what kinds of things people do when they are located in a particular place — is a major industry."

In its product launch, Facebook tried to address privacy concerns.

"Following the flaps created by earlier launches, Facebook seems to be taking a more moderate approach to location sharing," Jules Polonetsky, co-chair of the Washington-based Future of Privacy Forum told CBC News.

"Just about everybody recognizes location as something that you want to be in control of."

As a result, only your Facebook "friends" can see when you are tagged into a location and you can use your own friends' list to control who can see your check-ins.

Also, if a friend tags you at a location and you have not opted into Places, you will receive a notification that gives you two options: "Allow check-ins," which signs you up for the service, or "Not now," which disallows that particular check-in."

To completely opt out, you have to use the custom privacy settings page to permanently disable your Facebook friends from tagging you into locations.

A glitch?

Facebook has said that no location information will be associated with anyone unless that person explicitly chooses to become part of location sharing.

However, Michael Zimmer, an assistant professor at the University of Wisconsin-Milwaukee, found that when he tagged his wife as being with him at the liquor store, her name appeared on his wall and was visible to his friends, even though his wife had not authorized him to check her in.

"I was able to tag her in my check-in, and all my friends now see her name linked with my check-in as if she was there," he wrote in a blog post.

Facebook responded to Zimmer's criticisms saying that this was similar to him updating his status feed to say that he was at the liquor store with his wife.

But, as Zimmer told CBC News, "geographical updates need to be treated differently. They are more sensitive and personal than an average update."

Not easy to change

You can change your settings to get around some of these problems. But several privacy advocates say the Facebook settings are unnecessarily complex and that the default settings allow for users to have certain personal info exposed without their consent.

One of the features of Places allows other users, not just your Facebook friends, to see when you are checked into, say a popular restaurant, at the same time as they are.

If you are not interested in having strangers in the same location being able to see you, you can opt out of the Here Now feature by un-checking the "Include me in 'People Here Now' after I check in."

This can be found in the privacy settings under the "Things I Share" heading.

Once you have opted in to Places, Facebook applications, including your Facebook friends' applications can gather your location data.

The settings to stop your friends' applications from using your Places location data, can be found on the main privacy page under the "Applications and Websites" link.

However, as Marc Rotenberg, executive director of the Electronic Privacy Information Centre in Washington, D.C., says: "There is no single opt-out to avoid location tracking.

"It's not something you can easily control and users must change several different privacy settings."

One other big concern lies in what are called user-submitted places. That means, if a place doesn't exist in the database of well-known sites, users can add it and check in right away.

But if a friend decides to check in from, say, your home address, designating that a user-submitted place, there is no easy setting to remove that location page.

Users can report a place page that they believe violates Facebook's Statement of Rights and Responsibilities. But how quickly the page will be reviewed or what criteria will be used for removal is unclear.

At the press conference to announce the launch of Places, a Facebook engineer said, referring to user-submitted locations, "You can report it if somebody else created it. So if something is offensive or you don't like it, you can flag it, and if enough people do it we'll take it down."

But, if it's your home address that has been submitted, you might be the only one with the problem.