Yahoo, Microsoft, AOL and Earthlink have all joined in filing the first major lawsuits under the new federal Controlling the Assault of Non-Solicited Pornography and Marketing (CAN-SPAM) Act of 2003. The act went into effect Jan. 1.

Together, they filed six lawsuits naming hundreds of defendants in an effort to target the most active and nortorious spammers. The alleged spammers are all charged with direct violations of the CAN-SPAM Act, including:

• Deceptive solicitations.
• Use of open proxies (sending spam through third-party computers to disguise their point of origin).
• Falsified “from” e-mail addresses (spoofing).
• Absence of a physical address in the e-mail.
• Absence of an electronic unsubscribe option.

   Anyone who receives spam regularly will be annoyingly familiar with pitches for Super Viagra, mortgage refinancing, prescription drugs, cable descramblers and get-rich-quick schemes, among others. The key is that the defendants named are known to be the most prolific and harmful of spammers targeting consumers via the ISPs’ networks, the companies said.