The California Supreme Court sought to clarify how trespassing laws apply to the Internet as it heard arguments yesterday in Intel Corp.'s case against a former employee who sent mass e-mails to the company criticizing its employment practices.

Intel sued engineer Kourosh Kenneth Hamidi in 1998, claiming that he trespassed on its property by sending as many as 35,000 e-mails to employees after he left the company.

An appeals court agreed with a state court that prohibited Hamidi from sending unsolicited e-mails to Intel.

Hamidi appealed. He said that he didn't set foot on Intel's property and that sending e-mail isn't trespassing.

The trespassing law "has remained the same for hundreds of years and here it has been adapted to a confusing and difficult forum," Hamidi's attorney, William M. McSwain, told the court.

If the appeals court's decision stands, any form of electronic communication could be subject to trespassing law, McSwain said: "You can't get a trespass injunction for an unwanted phone call."

Intel argued that the e-mails burdened its servers and distracted employees.

"You have to imagine the swirl that takes place when these messages arrive," Intel's lawyer, Michael A. Jacobs, told the court. "Someone gets it and takes it to his manager, who then asks his supervisor what to do about it. It's a mini-firestorm."

The justices asked McSwain what he considered the criteria for trespass. "Thirty thousand e-mails on an unsolicited basis," Chief Justice Ronald M. George said. "It's almost like dumping vitriol of a verbal nature."

McSwain said there has to be a "physical touching of chattel" and "an element of physical damage or impairment."

"It would be extremely rare for an e-mail to damage a computer," McSwain said.

Business groups, free-speech activists and labor organizers filed more than a dozen advisory opinions in the case.

If companies can shut out e-mails, "Web sites or any device capable of receiving electronic signals suddenly becomes something that has an invisible fence around it," said Lee Tien, a lawyer with the Electronic Frontier Foundation, a civil liberties group that supports Hamidi. "You cripple the Internet by creating all these fences."

Intel isn't trying to regulate anything that's in public, said Mark Theodore, a lawyer who filed a brief supporting Intel on behalf of the U.S. Chamber of Commerce.

"Their server is connected to the Internet, but they're not seeking to go beyond their servers," Theodore said.

Intel said it has never tried to stop Hamidi from exercising his free- speech rights or to organize a union, and casts the case as simple trespass. "If he entered the facility and tried to leaflet, he'd have been thrown out," Jacobs said.