Scores of Web sites were taken off the Internet over the weekend because of new pressures on a commercial Internet service provider to stop unwanted marketing e-mail, or spam, and the companies that use it.
Most of the Web sites that were shut down had no relation to the company accused of sending spam other than having the same Internet service provider for their Web site. But in the escalating spam battles, some anti-spam groups seem to care little about collateral damage.
On Sunday afternoon, 89 Web sites operated by US Moneywerx, a Bryan, Tex., company that operates Web sites for small businesses, were disconnected.
They were cut off because Server Beach, the San Antonio company that actually houses US Moneywerx's server computer, reacted to complaints by the public and an anti-spam group who said that a site that had US Moneywerx as its host was sending spam.
Richard Yoo, the president of Server Beach, said he evaluated information provided by the group called the Spam Prevention Early Warning System that runs a Web site called Spews.org. That site added to its list of spammers a small Los Angeles company called NetGlobalMarketing, which was a client of US Moneywerx.
Many Internet service providers block e-mail not only from sites identified on the Spews.org list but from any company that provides Web services for those companies.
Executives of NetGlobalMarketing were quoted in an article in The New York Times last week on the efforts by e-mail companies to block spam. The article quoted company executives saying that all of the e-mail messages they send are to people who have requested e-mail offers. Nonetheless, the company has received thousands of angry and threatening e- mails and telephone messages over the last week. And personal information about company executives has been placed on anti-spam Web sites.
"I am not a spammer, and we do not spam," said Alyx Sachs, the company's co-founder. "I run a marketing company, and we use e-mail the way we use radio or print."
Don Wood, president of Childwatch of North America, an organization that tries to prevent abduction of children, said he sometimes hired NetGlobalMarketing to send e-mails to parents inviting them to events where their children can be photographed and fingerprinted.
Ms. Sachs said the company does work for dozens of well- established companies, including some in the travel, insurance and entertainment industries. But, she said, they do not wish to be identified because of the current reaction against spam.
"People are being wrongfully accused of spamming based on rumor, gossip and innuendo," she said.
Ms. Sachs expressed particular frustration with the Spews site, because there is no way to talk to anyone from that organization to protest being placed on that list.
The site is registered in Russia, and its operators are anonymous and offer no telephone number, address or e-mail address to contact them. Nonetheless, their list is widely used by Internet service providers looking to block spam.
Now even some other anti-spam activists have started to say that Spews is going too far.
"Spews is very aggressive," said Steve Linford, who runs the Spamhaus Project, another organization, based in Britain, that runs a list of known spammers.
Spamhaus, he said, tries to respond to complaints that it has unfairly put a company on its list, something that he said Spews did not do.
"They don't care what is blocked and will block anything around a spammer," he said. The effect has been powerful, he added, saying that "Spews has brought fear" to Internet service providers that house spammers.
The Spews site also does not appear to be very precise. Bhavin Chandarana, who runs a Web services company in India called Indialinks, said his firm has been listed by Spews because it has an Internet address similar to that of US Moneywerx.
Mr. Yoo, the owner of Server Beach, said that Spews has "a shoot-first-and-ask-questions-later mentality." But, he said that spam had become so much of a problem that it required what amounts to rough justice.
But caught in that pursuit of rough justice are companies like KWA Ecological Science, a Seattle consulting firm that specializes in salmon preservation. Its Web site and e-mail account are served by US Moneywerx and were shut down on Sunday.
"If someone took an action to cut spam out, I am a great supporter of that," said Keith Wolf, the Seattle company's owner.
"But this is not good for me, as I do most of my business working with large groups of people collaborating by electronic mail," he added.