A man walks up to a woman in a bar. Instead of shyly asking about her interests, he already knows them. He doesn't ask where she is from or where she went to school. After a furtive glance at his phone, he knows that, too.
He has an app for that.
This particular app is called "Girls Around Me" and like many other smartphone programs that provide fast and easy information, it uses publicly available data. For instance, Girls Around Me finds out what women recently checked in to a bar on the social media site Foursquare, alerts the user and provides a look at the woman's Facebook profile.
The app was taken down this year voluntarily by its creator, SMS Systems, after a hailstorm of privacy concerns from bloggers led by the Cult of Mac calling it a "stalker app." Many others exist to take its place in various forms as the world's smartphones increasingly become repositories for personal data.
Companies that produce the apps say they are harmless. SMS, based in Russia, said in a statement that all data it provides are already public, and it plans on bringing back another version soon. "The app just allows the user to browse the venues nearby, as if you passed by and looked in the window," SMS said in a statement.
Experts say millions of mobile users unwittingly share personal data everyday.
"What we are seeing now is just the top of the mountain," says Lee Tien, a senior attorney with the Electronic Frontier Foundation.
Among the apps causing alarm:
•Highlight, a mobile friend-finding app, monitors the location of its users, and notifies them if their friends and family, or complete strangers with similar interests, are nearby.
•SceneTap uses facial detection software to monitor bars and determine the age and gender of those in the crowd. The goal, said SceneTap's CEO Cole Harper in an open letter addressing privacy concerns, is for people to use "the app to find the scene that is right for them."
•Find Friends Nearby was Facebook's response to the trend. It was pulled for privacy concerns.