The new law in California "not only gives victims the ability to seek redress for themselves," Kramer said, "but it also creates a means of serving the public interest, because those suits create deterrent and the threat of those suits creates deterrent."

He said he hopes that the California law will not be abused as he believes the right to take private action has been in Utah, where the law allows a spam recipient to sue for $10 for every e-mail. There, two law firms have filed 1,500 individual lawsuits seeking $6,500 settlements with e-mail senders, said Kramer.

The California bill was backed by a variety of consumer advocates, who had made protection of residents' privacy a leading issue of the recently concluded legislative session.

Murray said the new law will require recipients to give their consent before receiving a sales pitch via e-mail, unless the individual and the entity had previously done business. In that case, the recipient could demand that no more unsolicited messages be sent.

In a statement, Davis said the California law will signal to the nation that the "time has come for unscrupulous spammers to stop feeding our e-mail boxes a daily diet of unwanted e-mail."

Several bills have been proposed this year in Congress that would restrict the use of commercial e-mail. Sen. Charles E. Schumer (D-N.Y.) has called for a federal anti-spam registry, similar to the do-not-call registries for telemarketers. That would enable consumers to prevent unsolicited commercial e-mail. And Sen. Ron Wyden (D-Ore.) has co-sponsored a bill that would impose stiff civil penalties on spammers who failed to include valid links allowing recipients to unsubscribe to unwanted e-mails.

Davis, however, warned against other federal legislation that threatens to overturn new privacy measures in California and nullify several existing identity-theft laws.

One potential target is the heavily contested California law that requires banks and other financial institutions to first obtain a consumer's consent before his or her private financial history can be sold or traded to third parties for marketing purposes. The law also clamps restrictions on which companies in a business family can and cannot receive such information without the customer's advance approval.

Legislation is moving in both houses of Congress that would throw out the law, written by state Sen. Jackie Speier (D-Hillsborough), on grounds that state laws cannot be stricter than federal laws.

Instead of wiping out California laws, Davis said in a letter to congressional leaders, "Congress should consider them as a model for the rest of the nation."

He said that, if nothing else, the federal legislation should exempt California.

In the Legislature, the Murray proposal drew surprisingly little opposition.

But the California Assn. of Realtors expressed fear that the bill would limit its ability to send electronic notices of trade shows and seminars to its 130,000 members.

Stan Wieg, an association lobbyist, said it would be hard for local chapters, often run by volunteers, to keep up on who does and doesn't want such information.

"You can see how you can be tripped up by that sort of record-keeping obligation," he said.

The direct-marketing industry, which opposed other privacy bills, did not fight the Murray proposal. But industry observers warned that the new law would not touch the most notorious spam merchants, which are based outside the United States.

"It fails to address the core issue about spam. It totally fails to be able to reach the offshore criminals who are sending Viagra ads," said Ray Schultz, editorial director of Direct, a magazine that covers the direct-marketing industry. He said the industry would prefer to see a uniform federal law that supersedes state statutes.

Another bill signed Tuesday by Davis was SB 27, which will require firms that have divulged a customer's personal financial information to others to inform the customer, upon request, which third parties received the information and what it contained.

Times staff writer Nancy Vogel contributed to this report.