By JOSEPH BERGER
His blogger pen name is Shtreimel, the Yiddish word for the round fur hat that a Hasidic man wears on Sabbath.
He styles himself a heretic, a Brooklyn Hasid with beard and earlocks who does not believe in God, sneaks away to snack on Yom Kippur and sometimes grabs a hamburger that isn't kosher at McDonald's. On three blogs that he has kept - changing them like safe houses out of fear of exposure - he has confided his spiritual misgivings and mused about hypocrisies he sees among Hasidim, like a willingness to beat up adherents of a rival sect.
Within his community, he scrupulously keeps up appearances because, he said, if he were ever identified as an iconoclastic blogger he would be ostracized and might lose his wife and children.
"People can get connected to each other, and once ideas that are not implanted by the establishment spread, they can explode," said Shtreimel of the Internet, speaking at a Starbuck's on the condition that he and his sect not be named.
Although he and other cyberspace renegades make up a sliver of the ultra-Orthodox world, leaders of insular Orthodox communities are coming to regard the Internet - a gateway to louche American culture and the voices of doubters - as treacherous, even subversive, and are grappling with how far to go in outlawing its use.
Just before Rosh Hashanah, the Orthodox schools and institutions of Lakewood, N.J., a community of 6,500 families in Ocean County, issued a proclamation forbidding children and high school students from using Internet-linked computers.
"Many children (and adults) have fallen prey to the immoral lures that are present on the Internet, and their lives have been destroyed," the seven-page proclamation began.
It barred even adults from going online at home except for the needs of a livelihood - and then only with rabbinical authorization.
Other faiths have also grappled with the Internet, though outright bans are rare. In 2000, the United States Conference of Catholic Bishops adopted a "user beware" policy that warned parents to exercise some common-sense precautions like filters to ward off pornography.
More liberal Orthodox believers see the Internet as "an unbelievable tool" that must be used with sensible precautions, said Rabbi Kenneth Brander, dean of the Center for the Jewish Future, a division of Yeshiva University.
"Judaism does not believe in a Robinson Crusoe type of lifestyle," he said. "Our responsibility as Jews is to bring light into a larger society, and you don't do that by retreating."
For many zealously Orthodox Jews, the Internet is fraught with paradox. In some ways, it has proved a godsend. Knowledge of the Talmud is spread on dafyomi.org. The site onlysimachas.com is a bullhorn for gossip about marriages and births. At aish.com, a round-the-clock view of the Western Wall in Jerusalem is offered.
One Hasidic sect, the Lubavitch, aggressively uses the Internet to disperse its messianic message on sites such as Chabad.org.
"The rebbe taught that everything in this world is created for a divine purpose," said Rabbi Zalman Shmotkin, a spokesman for the Lubavitch, referring to Menachem Mendel Schneerson, the grand rabbi who died in 1994. "The medium itself is neutral. How we use it makes all the difference."
In the heavily Hasidic Borough Park section of Brooklyn, Touro College operates an institution called Machon L'Parnassah - or preparation for a livelihood - which instructs young men and women to use Internet-linked computers for such careers as medical billing. Issac Herskowitz, chief academic computing officer, took pains to note that computer labs are always supervised to avoid private surfing.
So many haredim depend on the Internet for their livelihoods that the irony was not lost on them that the Lakewood ban displayed a keen sophistication about the Web.
Hella Winston, author of "Unchosen: The Hidden Lives of Hasidic Rebels" (Beacon Press, 2005), said Hasidim have had to confront the fact that the Internet has sparked Craigslist advertisements for liaisons between "frum," or observant, married people and has made available explorations of maverick philosophers.
And Shtreimel is not alone in posting his doubts in a public forum (conartistic.blogspot.com is his latest address).
Hasidim and other haredim have never been Luddites opposed to technology. But in building what they call a fence to safeguard Torah observance, they discourage enrollment in college, and social contacts between men and women. Some yeshivas will expel a child if they learn the family has a television.
"If television wasn't banned, we wouldn't have kids studying and learning Torah 16 to 18 hours a day," said Rabbi Shalom Storch, principal of Yeshiva Nesivos Ohr, a day school in Lakewood.
In Lakewood, the rabbis were spurred not by worries about dissension but by the dangers of the Internet for young people. They were troubled by online chats they heard about, like one between an 8-year-old yeshiva student on Long Island and a predatory adult.
Shtreimel said that he first dipped into the Internet out of curiosity and soon was confiding his religious skepticism in e-mail messages. Now he gets about 300 readers a day on his blog and savors writing for the same reasons other writers do.
"When I get a comment from a person and he says he likes what I wrote, that's good," he said.