The lawsuits, against defendants in California, Florida, Nevada and Washington, accuse the spammers of violating several state and federal laws including the Controlling the Assault of Non-Solicited Pornography and Marketing Act (Can-Spam).
But although welcomed, some have questioned whether the lawsuit will be successful.
"It's good news," said Steve Linford, director of anti-spam organisation Spamhaus. "Earthlink have done a fantastic job so far but unfortunately it often amounts to little. The spammer is let off with a slap on the wrist. Take Ryan Pitylak, he's already operating elsewhere."
Earlier this year Pitylak was accused of heading up a massive spam outfit from his Nevada registered companies.
Amongst the most recently accused is Gregory Lars Alsing, of Elk Grove in California, who allegedly sent tens of thousands of fraudulent emails advertising de-scramblers promising free cable television. He used random strings of text to bypass spam filters searching for recognisable spam traits.
Earthlink has had some notable success in the spam-fighting arena. Howard Carmack, also known as the "Buffalo Spammer", was forced to shut down his spam operation and shell out $16.4 million after losing his case against the ISP.