The Marquis de Cyberspace By: WENDY COLE SPRINGFIELD Four months into his three tear sentence for transmitting obscene images by computer, the man the Carnegie Mellon report calls a modern-day Marquis de Sade hardly looks like a political cause celebre. Robert Thomas spends his day like any other inmate at the U.S. Medical Center for Federal Prisoners in Springfield, Missouri: cleaning the prison kitchen and laundry room and waiting to hear whether his lawyers win get him out on appeal. Thomas's case could well end up in the Supreme Court, where it would set legal precedent for all of cyberspace. Thomas, 39, operator of the Amateur Action BBS in Milpitas, California, made headlines last year when he and his wife Carleen, 40, were indicted for transmitting pornographic material to a government agent in Tennessee. A jury in Memphis wasted little time ruling that the images, which included pictures of women having sex with animals-were obscene. But his case raised the tricky constitutional question of which locale's or community standards should have been used to make that judgment: Tennessee's Bible Belt, California's Bay Area or the virtual community of cyberspace? Though he concedes that many might find his stockpile of 25,000 photos featuring S&M and hard-core sex distasteful, Thomas insists he violated no laws. "I don't feel I committed a crime because I didn't offend anybody but a postal inspector in Memphis," he says, referring to the government official who launched the investigation. Thomas also faces charges in Salt Lake City of distributing images of naked children, but he insists those images aren't sexually explicit. "They are from nudist colonies," he says. "Many of them are family snapshots." On-line porn certainly pays, Thomas' income last year topped $800,000, enabling the slight, shaggy-haired Californian to indulge in his two extracurricular passions: expensive cars and exotic birds. Subscriptions have more than doubled (to 7,000) since his arrest. Some of the newcomers aren't even bothering to download the dirty pictures; they seem to be offering their $99-per-year subscription fees as donations to the cause. The extra income will come in handy, since the Thomas's legal bills are approaching $250,000. Thomas didn't set out to make headlines or case law. A former furniture mover with an interest in computers, he opened his BBS in 1991 with 12 photos and a single phone line. He worked hard. He regularly put in 16-hour days, sometimes staying up all night to scan new, hard-to-find photos for his collection. At the time of his indictment he was spending $500 a week on fresh material, much of it sent by scouts as far away as Denmark and Brazil. The slogan for his bulletin board came from closer to home, however. He was inspired by a visit to Disneyland, where a sign outside proclaims it THE HAPPIEST PLACE ON EARTH. His computer system came to be known as "the nastiest place on earth." Whatever else might be said about him, Thomas does seem to have a flair for marketing. The trick, he says, is in how you write the pitch lines that describe your pictures. "You want to make the descriptions like a menu," he explains. "If your selling a dry, tough steak, you want to make it sound as juicy as you can." Among his favorite come-ons (and one of the few suitable for publication): "Peek into the bathroom and see this cutie sitting on the toilet!" A subscriber who chose to download that photo would get a digitized picture of a 15-lb. lobster.