EarthLink Inc, the third-largest US Internet-access service, said it will offer software to its subscribers that can block "virtually 100 percent" of their spam e-mail.
The new "spamBlocker" will be offered for free to EarthLink subscribers starting tomorrow, the Atlanta-based company said in a statement.
EarthLink will begin an advertising campaign, including print and television ads, for the new software in late summer or early fall, said Jim Anderson, the company's vice president of product development.
The amount of spam, or unsolicited commercial e-mail, through EarthLink's system has risen more than fivefold over the past 18 months, Anderson said.
An analyst said the spamBlocker program is likely to block some e-mail that isn't spam and that businesses that send spam will eventually find a way to circumvent the program.
"I have a much higher degree of confidence in spammers' ability to outsmart technology than I have in technology's ability to defeat spammers," said Jim Nail, an analyst with Forrester Research Inc in Cambridge, Massachusetts. Nail said he doesn't own EarthLink shares.
EarthLink subscribers who download spamBlocker will only receive e-mail from senders who are listed in their personal address books, Anderson said.
SpamBlocker requires senders of e-mail who aren't known to the recipient to fill out a short questionnaire. EarthLink will then send an e-mail to the recipient giving them the option of adding the sender to their address book.
"The vast majority of communications are going to be from people you know," Anderson said in an interview. "What we've done here is taken a permission-based approach."
The software also contains the features of the "spaminator" software that EarthLink's previously distributed, Anderson said.
That program identifies senders of mass commercial e-mail and blocks them. It stops 70 percent to 80 percent of junk e-mail, he said.
Forrester's Nail said the spamBlocker is similar to software offered by Mailblocks Inc, of Los Altos, California.
Nail said he's tested Mailblocks' software and found that it stopped some e-mail that wasn't spam.
"A couple of my friends have not been able to figure out how to get through the challenge," he said.
Mailblocks said three weeks ago in a statement that it has sued EarthLink alleging patent infringement.
"We've reviewed the complaint and we vigorously defend our position," EarthLink spokesman Jerry Grasso said.
The growing volume of spam e-mail, much of it for products such as mail-order Viagra and financial schemes, is taking up computer-users' time and hard drive space.
Two-thirds of junk e-mail contains false or deceptive claims, the US Federal Trade Commission has said.
EarthLink, with 5 million subscribers, has filed lawsuits against senders of spam. The company won a US$16 million judgment three weeks ago and a court order for Howard Carmack, of Buffalo, New York, to shut down his e-mail operation.
EarthLink charged that Carmack had used hundreds of stolen credit cards and fake identifications to open 343 e-mail accounts that sent 1 million spam e-mails a day.
Carmack was arrested two weeks ago on charges of identity theft. At his arraignment, he entered a plea of not guilty.