AOL, Microsoft, EarthLink and Yahoo -- members of the Anti-Spam Alliance --have all filed lawsuits against the US courts.
This includes a case brought by AOL against 20 individuals accused of spimming, or sending unsolicited junk mail over to an instant messaging client or to a chat room.
A second AOL lawsuit, against 10 people suspected of selling controlled drugs online, is the first time that the Internet service provider has relied on complaints from its European and Canadian customers.
"AOL and our members continue to make spam-fighting a priority, and we continue to use the legal process on their behalf to help put a lid on the worst, most active spammers – no matter where they are, or how they send their unwanted junk,” said Randall Boe, AOL's general counsel, in a statement.
Microsoft has brought lawsuits against three people it accuses of using open proxies to route millions of emails soliciting herbal growth supplements, mortgage services and get-rich-quick schemes, all in violation of the CAN-SPAM federal law.
EarthLink and Yahoo have also filed one lawsuit each, alleging violations of CAN-SPAM and various other federal and state laws in emails sent to their users.