Microsoft said today it had filed lawsuits against those it claimed were responsible for flooding its MSN Internet service with more than 2 billion unsolicited e-mail messages.
The company also vowed to step up its campaign against spam in the courts.
The world's largest software company said it had filed 15 lawsuits in the United States and Britain against spammers that had sent unsolicited e-mail touting everything from get-rich-quick schemes to pornographic websites.
In April, Microsoft, AOL Time Warner's America Online unit and Yahoo! - which represent the world's largest block of e-mail users - said they were working together to block unidentified messages and to stop spammers from creating fraudulent e-mail accounts.
According to a report by Forrester Research, North American online users said more than one-third of their e-mail is junk mail, with the average consumer getting bombarded with 110 unwanted e-mail messages every week.
Separately, the United States and 29 other countries announced an effort yesterday to track down spammers, telemarketers and other scam artists who operate across international borders.
The agreement would make it easier for governments to investigate and apprehend cyber-scam artists who operate on a global basis, officials with the US Federal Trade Commission and several other countries said.
Complaints about international fraud nearly doubled to 30,798 last year, according to FTC statistics.