When you Google &#8220anti-acne remedies,&#8221 send a Tweet, sign up for Farmville on

Facebook or use Yelp to find the nearest sushi restaurant, you open a digital window into your

life.

Those services collect and store reams of this personal data from millions of users,

creating a potential gold mine for the companies and advertisers.

But can we trust them to protect our privacy?

&#8220The largest, most-profitable unregulated industry in America is data and data

mining,&#8221 said John A. Curr III, executive director of the Western regional chapter of the

New York Civil Liberties Union.

Facebook, Google and Twitter have come under fire in recent months from consumers and

privacy advocates, who contend the companies have compromised personal data or made it harder

for users to secure.

The privacy breaches are prompting members of Congress and federal officials to consider

stricter rules to protect our personal data.

While consumers worry what companies may be doing with their data, these same consumers

share vast amounts of intimate information online.

They freely post phone numbers, home addresses, birth dates, photos and other identifying

details on Web sites.

&#8220That data lasts forever. It doesn&#8217t go away,&#8221 said Anthony G. Basile,

information technology chairman at D&#8217Youville College.

With the growth in GPS technology and mobile devices, users of services such as Foursquare

now can reveal their movements to friends, strangers &#8212 and savvy criminals.

These locational services are leading to personalized ads that speak to you from TV screens

and coupons that pop up on your mobile device as you walk into a restaurant or store.

But skeptics warn that consumers should weigh how much personal information they give up to

get a coupon for a latte.

&#8220Consumers need to be careful about letting marketers have unfettered access to a

digital-data Fort Knox of information about them,&#8221 said Jeffrey Chester, executive

director of the Center for Digital Democracy.

Kate Holzemer, a viola player with the Buffalo Philharmonic Orchestra, takes the attitude

that anything she writes on Facebook has entered the public domain, even though she keeps her

privacy settings high.

&#8220I hold back a lot of information about where I am, if I&#8217m out of town. I never

reveal my exact location at any time,&#8221 said Holzemer, the Kate Bits blogger.

Adrian Roselli regularly posts pictures of the meals he has made or eaten, such as the

penne with chicken in vodka sauce he enjoyed Wednesday night at Amici Ristorante & Cafe in

Kenmore. But he won&#8217t put online a photo of other people unless he has their permission.

When Roselli finds out about a new service, he tests it through a fake account before

deciding whether he is comfortable using it under his own name.

And on Facebook, he doesn&#8217t say who he is related to or who he is dating, and he

doesn&#8217t &#8220friend&#8221 his family members, all to limit how much people can find out

about him.

&#8220You don&#8217t have to give up information to participate in the world,&#8221 said

the senior usability engineer at Algonquin Studios.

The information that users post on their profiles can reveal more than they intended.

Two Massachusetts Institute of Technology students developed a software program that

predicted with a high degree of accuracy whether a Facebook member was a gay man, a project

dubbed &#8220Gaydar,&#8221 the Boston Globe reported.

And Carnegie Mellon University scientists used social-networking sites to accurately

predict the full, nine-digit Social Security numbers for 8.5 percent of the people born in

this country between 1988 and 2003, according to the school.

&#8220The more information people have about you, even if it looks innocent, then the more

they&#8217re going to be able to harm you,&#8221 D&#8217Youville&#8217s Basile said.

Preserving privacy has been an ongoing issue for these services.

In May, Facebook produced a near-mutiny among some members when it introduced a service

that automatically gave other Web sites, such as Pandora and Yelp, access to users&#8217

personal information.

Fifteen consumer groups filed a complaint with the Federal Trade Commission in response.

A &#8220Quit Facebook Day,&#8221 set for May 31, persuaded nearly 37,000 people to pledge

to leave the site &#8212 but that&#8217s a fraction of Facebook&#8217s 400 million users.

Sen. Charles E. Schumer, D-N.Y., was one of four senators who wrote a letter to Facebook

founder Mark Zuckerberg, urging him to give users &#8220full control&#8221 over their personal

data.

In June, Facebook launched a privacy page, www.facebook.com/fbprivacy. The company also

made it easier for users to block features that give third-party Web sites their personal

information.

Google has had its own privacy issues. A class-action suit filed in February alleges that

the Google Buzz social-networking service shared personal data without the consent of users.

In June, Google denied violating federal law when its Street View cars picked up data from

unsecured Wi-Fi networks.

The FTC and Congress are showing more interest in the issue of online privacy, but the

NYCLU&#8217s Curr wants to see a &#8220bill of online rights.&#8221

Alan Bedenko, the Buffalo Pundit blogger, uses Foursquare to check in at the Whirlpool

Bridge, Buffalo City Hall and the Hatch restaurant.

Someone who isn&#8217t friends with Bedenko can see basic information, such as his total

number of check-ins, his badges and his tip to try the she-crab soup at Black & Blue Steak and

Crab.

They can&#8217t see where Bedenko is checking in, but Bedenko links his Foursquare updates

to his Twitter feed, which is public.

Bedenko said he never checks in at a location where he is dropping off his children, such

as their day care center, and he hasn&#8217t listed his home address.

But he said he isn&#8217t worried if people know where he is, and he doesn&#8217t mind if

companies have this information.

&#8220I&#8217m not by nature a paranoid person. If they&#8217re going to use that

information, they&#8217re going to use it to market to me. They&#8217re not going to use it

for something evil,&#8221 Bedenko said.

Locational data is valuable to advertisers because it gives these firms an unmatched

insight into where consumers spend their time and money.

If someone using Foursquare regularly checks in at McDonald&#8217s, the chain can send a

coupon for a Big Mac to your smart phone, for example.

Or if Banana Republic knows that you shop on its Web site, and it sees that you are

visiting Walden Galleria, it can connect the dots and try to lure you into its store with an

ad.

But do we really want marketers knowing when we pick up a prescription at a pharmacy or

whether we visit adult bookstores?

&#8220Location-based data is a privacy catastrophe waiting to happen,&#8221 said Peter

Eckersley, senior staff technologist with the Electronic Frontier Foundation.

The people who use these sites say they are willing to give up some personal data in

exchange for the value of these services and the occasional targeted ad.

It&#8217s clear this technology is embedded in our lives today.

Asked if she could give up Facebook, Colleen Callahan paused, laughed and said,

&#8220No.&#8221

&#8220It becomes part of your connection to people,&#8221 said Callahan, associate director

for Web community and development in the college relations office at Buffalo State College.