New York Attorney General Mr Eliot Spitzer is suing a firm he says sent more than 500 million messages to computer users, many of them unwanted "spam" advertisements.
Mr Spitzer says MonsterHut.com of Niagara Falls sent hundreds of millions of the ads through e-mails since March 2001 to people who didn't want the messages or specifically tried to block the stream of commercial offers. MonsterHut.com had told its clients that the recipients wanted the messages through "permission-based" agreements, according to court records.
About 750,000 computer users complained about receiving MonsterHut.com spam, or junk mail, Mr Spitzer said.
Spam comes from many sources worldwide and increasingly clogs e-mail systems with pitches that include ways to lose weight, earn extra income or view pornography.
"Some of the spam is a vehicle for fraud, some of the spam is inherently fraudulent and much of it constitutes a real annoyance for e-mail users," Mr Spitzer said.
Earlier this month PaeTec Communications of the Rochester area, an internet provider, threw MonsterHut.com off its network after a 13-month court battle.
Tens of thousands of customers complained about the spamming, said Mr John Messenger, vice-president of the Fairport-based PaeTec.
Anti-spam organisations - a growing field - threatened to urge boycotts of PaeTec.
"As soon as we turned on their service in March of 2001, we immediately began receiving complaints," he said.
The spamming affected so many complaints that PaeTec created a website (http://www.litigation.paetec.net) to provide the information to customers without fielding thousands of calls. The site contains court records from Paetec's case against MonsterHut.com.
MonsterHut.com fought PaeTec's decision to drop the e-mail firm with a court injunction.
MonsterHut officials didn't immediately respond to a request for comment. Its website is no longer active.
Since the mid-1990s, internet service providers America Online, EarthLink and others have won millions of dollars in settlements and judgments against spammers under trespass, computer fraud and other laws.
Mr Spitzer is suing under the state's traditional deceptive practice and false advertising statutes that could exact civil penalties of $500 (€536) for each offence.
Nineteen other states now have anti-spam laws that prohibit false messages or headers in e-mail messages, require labels in subject lines or the option of declining a marketer's future mailings.
