A year ago, Maldonado’s computer stopped working and she cannot afford a new one. So almost every day she borrows one of the library’s laptops and sits down at a desk, rushing to submit customers’ orders online or research and write papers for her medical billing class before the library closes.

When she returns to her apartment, she rummages through her purse and places whatever money she can spare in a jar half-filled with coins and crumpled dollars. She’s saving to buy a laptop — and grasping for a lifeline in the digital age.

“My teacher assumes everyone has Internet at home,” she said. “I feel like I’m being left behind.”

Maldonado is not alone. She is one of an estimated 100 million Americans who have no way of accessing the Internet at home. She and others are on the wrong side of the so-called “digital divide” — the chasm between those who are connected to technology and those who are not. Some live in remote areas where broadband service doesn’t exist. Many live in blighted urban neighborhoods, unable to afford a computer, let alone Internet service. In the Bronx, for example, where the median household income is about $34,000, less than 40 percent of residents have broadband access at home — the lowest of the five boroughs, according to a 2008 report for the New York City Council.

But being disconnected isn’t just a function of being poor. These days, it is also a reason some people stay poor. As the Internet has become an essential platform for job-hunting and furthering education, those without access are finding the basic tools for escaping poverty increasingly out of reach.

“The cost of being offline is greater now than it was 10 years ago,” said John Horrigan, vice president of policy research at TechNet, a trade association representing high-tech companies. “So many important transactions take place online. If you don’t have access to high-speed Internet, you’re missing out on a lot.”