A Florida man and his company must pay a $25,000 fine to settle a spam case filed against him by US state Massachusetts' attorney general.

Attorney General Tom Reilly said William C. Carson and his business, DC Enterprises, agreed to pay the fine and to stop sending thousands of unsolicited e-mails.

Carson and his company allegedly sent thousands of commercial e-mails from a business address in Massachusetts, where the company had no physical presence. The allegations were outlined in a June lawsuit brought by Reilly, which described how the company's actions violated the Massachusetts Consumer Protection Act and the federal CAN-SPAM Act, which went into effect at the start of the year.

"Internet marketers should note that Massachusetts takes seriously federal and state laws meant to protect against unwanted and misleading e-mails," Reilly said in a statement. "These messages are the type of unwanted and annoying solicitations that have become the scourge of Internet users and threaten the credibility of companies using e-mail for legitimate purposes."

Carson used an invalid business address in his messages. The complaint also said he failed to clearly identify messages as advertisements and used a non-functioning sender address, all of which violate federal and state anti-spam laws.

The Massachusetts lawsuit was the first enforcement action taken by a state under the CAN-SPAM Act, according to Reilly's office. It also helps add to the increasing body of law against spammers in the US - where a majority of the world's spam comes from.