Robert White, the director of the network, said he had calculated that “the average yearly value to every card used in our system was $706.”

“You don’t get that kind of rebate on the Discover Card,” Mr. White said. “And it’s all free.”

As in Ms. Weiss’s case, librarians said they were noticing more adults getting library cards for the first time, or sheepishly explaining that they had lost their cards or even paying long-neglected late fees so they could use the library’s free Internet service.

Jude Schanzer, the director of programming at the East Meadow Public Library, on Long Island, tells the story of a middle-class woman in her 50s who dropped in late last year after work and applied for a library card. She confided to a librarian that it was the first library card she had possessed since childhood.

“Now I don’t have to buy my books,” she told Ms. Schanzer. “This is how I’m cutting back.”

In Ridgefield, an affluent Connecticut town where many residents work at nearby companies like Pepsi, General Electric and I.B.M., people are tapping the public library’s free services even if they are financially comfortable enough for now, library officials said.

“I just think people are hunkering down,” said Christina Nolan, the library’s director. “They may not have to cut out Netflix, but they’re choosing to do so because they don’t know what’s around the corner.”

Indeed, as Ms. Nolan spoke, Ann Harrington, a mother of two married to a freelance illustrator whose assignments, she said, were slipping, was carrying a half-dozen DVDs, including “A Few Good Men” and “The Upside of Anger,” as well as the inspirational football film “Facing the Giants,” which her whole family could watch.

Ms. Nolan said attendance was up 20 percent at the library’s abundant  and free  weekend and weeknight programs, with residents opting for those rather than tickets to Broadway or Lincoln Center or a movie at the multiplex. Ms. Nolan has shown the Batman movie “The Dark Knight” and “Man on Wire,” the documentary about the Twin Towers tightrope walker, to packed houses of about 100 people, something she said would not have happened a year ago.