A US internet firm has won $16.4m (£10.3m) damages and a permanent injunction against someone who sent 850 million unsolicited e-mails via its service.
EarthLink, the number-three US internet service provider (ISP), argued that Howard Carmack and his accomplices had fraudulently purchased hundreds of accounts on its service.
These were then used to mail out advertisements for get-rich-quick schemes, miracle cures, software and cable TV descramblers.
Although EarthLink feels there is little chance of enforcing the damages payment, it said it was cheered by the injunction, which bans Mr Carmack from any future involvement with bulk e-mailing.
EarthLink, like other large ISPs, is becoming increasingly concerned at the volume of unsolicited e-mail, or spam, passing through its system.
According to some estimates, up to half of all e-mail traffic worldwide is composed of spam.
This is the second major judgement that EarthLink has won against spammers.
Last year, it was awarded $25m in a case against an e-mailer who had sent out more than 1 billion messages.
AOL, the world's biggest ISP, was won more than 25 spam-related cases, but has not yet been awarded a sizeable payout.
The US and other governments are also preparing various cases against individual spammers, and legislators in various countries are mulling rules to make such e-mails illegal or harder to send.
Some internet experts are concerned that too heavy-handed a crackdown may stifle free expression.
At the same time, EarthLink is itself being sued by a business rival.
Silicon Valley-based MailBlocks has accused EarthLink of infringing some of its patents on spam-screening technology.
MailBlocks recently launched a paid facility that demands senders verify their bona fides before mail is delivered; EarthLink's similar but free service, the firm has claimed, is suspiciously similar.
MailBlocks has already sued three other firms for the same reason.
The case indicates the growing competition to produce an effective way of blocking spam without interfering with the movement of legitimate e-mail.
Having previously focused on ways of blocking material from unknown users, spam-busters are now focusing on more intelligent systems that allow senders to identify themselves.