Like most San Franciscans, Charles Pitts is wired. Mr. Pitts, who is 37 years old, has accounts on Facebook, MySpace and Twitter. He runs an Internet forum on Yahoo, reads news online and keeps in touch with friends via email. The tough part is managing this digital lifestyle from his residence under a highway bridge.

"You don't need a TV. You don't need a radio. You don't even need a newspaper," says Mr. Pitts, an aspiring poet in a purple cap and yellow fleece jacket, who says he has been homeless for two years. "But you need the Internet."

A few years ago, some people were worrying that a "digital divide" would separate technology haves and have-nots. The poorest lack the means to buy computers and Web access.

Still, in America today, even people without street addresses feel compelled to have Internet addresses.

New York City has put 42 computers in five of the nine shelters it operates and plans to wire the other four this year. Roughly half of another 190 shelters in the city offer computer access.

The executive director of a San Francisco nonprofit group, Central City Hospitality House, estimates that half the visitors to its new eight-computer drop-in center are homeless; demand for computer time is so great that users are limited to 30 minutes.

Shelter attendants say the number of laptop-toting overnight visitors, while small, is growing.

SF Homeless, a two-year-old Internet forum, has 140 members. It posts schedules for public-housing meetings and news from similar groups in New Mexico, Arizona and Connecticut. And it has a blog with online polls about shelter life.

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