You make a call from your land line or text a friend from your smartphone. You browse an online retailer for clothing, a book or music; you create a wish list or write a review.
You walk past a security camera outside your home; you use GPS to find your way to a business meeting. At the supermarket, you buy groceries with a credit card. Or you pay cash — but enter a loyalty card for the discount.
As you move through the ordinary activities of everyday life, you're leaving an electronic trail rich in data about your whereabouts, your interests and your relationships.
That's information of keen interest — and not only to marketers. As recent revelations about two National Security Agency surveillance programs show, at least some of those digital details are being collected and analyzed by the government.
President Barack Obama acknowledged Friday that the surveillance agency based at Fort Meade in Anne Arundel County has been collecting data on telephone calls made by U.S. citizens and monitoring the Internet and email use of foreigners as part of the nation's effort to combat terrorism.
Uproar over the two secret programs has sparked the latest round in the political and societal debate familiar to every American since the attacks on New York and Washington on Sept. 11, 2001: How far should the government reach into the lives of its citizens in the name of security?
What's new, however, is the vast proliferation of personal information now available for the taking. Facebook didn't exist when Congress passed the Patriot Act in 2001. And the first iPhone wasn't issued until more than five years later.
From 2002 to 2012, the number of wireless connections in the United States — including smartphones, tablets and other devices — more than doubled, from 141 million to 326 million, according to the industry group CTIA The Wireless Association.
Amy Webb, CEO of WebbMedia Group, a digital strategy consulting firm based in Baltimore, says the growth of technology and its incorporation into everyday life have outpaced the public's understanding of the privacy implications.
"We've got a whole bunch of people using these devices, and they're magical," said Webb. "But there are sacrifices that we make for that convenience. And one of those sacrifices is that our data is not totally locked down and reserved anymore just for us."
Obama said the telephone and Internet surveillance activities first detailed by the British newspaper The Guardian and The Washington Post were approved by the federal court that considers the legality of such surveillance and that Congress is briefed regularly. Lawmakers of both parties, including Rep. C.A. Dutch Ruppersberger of Baltimore County, the top Democrat on the House Intelligence Committee, have said such programs are needed to thwart terrorists.
Others raise privacy concerns. John Bacci, president of Foundation Financial Advisors in Linthicum, is a customer of Verizon, the telephone carrier named in a leaked order that for the first time documented that the NSA is collecting millions of phone records.
"It's another inch of ground we yield on the road to less freedom" in the name of security since the Sept. 11 attacks, Bacci said. "It seems like a million and one inches of ground. Suddenly, you have gone a long way."
James Hardesty, another Verizon customer, sees a trade-off.
"Anybody who doesn't think their phone calls haven't been monitored for the last 30 years has not read a spy novel," said Hardesty, chairman of Hardesty Capital Management in Baltimore.
He said the surveillance — in which the government collects details such as phone numbers and call duration but does not listen to the calls themselves — probably has prevented terrorism. He said he wouldn't lose any sleep over the NSA watching his phone activity.
"There are some bad people in the world," Hardesty said.
Michael Greenberger, founder and director of the Center for Health and Homeland Security at the University of Maryland, Baltimore, said the scope of NSA surveillance of what professionals call "telephony metadata" is likely to go far beyond what has been reported.
"I'm sure we are going to find out it's not just Verizon, it's everybody," he said. The program's disclosure, he predicted, "is going to be tough for the American people to digest."
"The initial reaction is one of great shock," he said. "Some people will say, 'If that can head off another Boston Marathon [bombing], then have at it.' "