SAN FRANCISCO -- 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."  Mr.
Pitts's experience shows how deeply computers and the Internet
have permeated society. 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.  Homeless
and Online  Skip Schreiber goes online in his van, which is also
his home, i