AOL buys Mailblocks in spam-fighting effort

America Online Inc. (AOL) has snapped up Web-based e-mail company Mailblocks Inc. in an effort to bolster its own e-mail services with greater antispam protection, mail management, and interface improvements, it said Wednesday.

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AOL did not specify the terms of the deal but said that the buy of privately held Mailblocks was aimed at gaining its challenge/response technology for fighting spam and authenticating legitimate e-mail senders.

Mailblocks' technology works by "whitelisting," or approving, everyone in a user's address book as a legitimate e-mail sender, and challenging any unknown senders. When a user receives an e-mail from an unknown sender, the service holds the mail and sends back an automatically generated message, asking the sender to type in the seven-digit code that they see on the screen. Once the sender enters the code, the message is delivered to the recipient and that sender will not be challenged again. The technology aims to defeat mass-mailer spam and worms generated by computers.

"This technology fits very nicely into our antispam strategy," said AOL spokesman Nicholas Graham.

Graham said that the acquisition closed early last month and Mailblocks' team already moved from the company's previous headquarters in Los Altos, California, to AOL's Mountain View, California, campus.

"One of the most appealing and attractive aspects of this acquisition is the fact that Mailblocks has a dedicated and energetic team of engineers," he said.

AOL said that it plans to make Mailblocks' challenge/response technology available across the AOL service as an option for members who want to use it, both via the "Mail & Spam Controls" menu and for users accessing their mail on the Web. The company said that it would integrate the technology through a series of phased upgrades.

Some of Mailblocks' user interface and mail management features will be integrated into the AOL services for accessing mail over the Web at AOL.com and Netscape.com later this year, Graham said. In a second phase, the challenge/response technology will be added as an option to the AOL e-mail service.

"We realize that challenge/response is not for everyone but we want to give our users a variety of options to fight spam," he said.

The Dulles, Virgina-based Internet company recently come out in support of a new e-mail protocol called Sender Permitted From (SPF) that attempts to crack down on spammers by eliminating forged e-mail addresses. Graham said that the challenge/response technology complements SPF in that they both have the function of "cutting a huge swath out of spam" by challenging the sender.

Mailblocks was founded by the late Phil Goldman, who was also one of the founders of WebTV Networks Inc., and commercially launched in 2003. The company's e-mail service targeted home and small business users, with a basic service priced at $9.95 a month and a premium service priced at $24.95 a year, according to Mailblocks' Web site. A free service was also available but as of Wednesday, it was not accepting any new users.

The company also offered to cobrand the service with original equipment manufacturers, as well as license the challenge/response technology to enterprise e-mail providers, according to the Mailblocks' Web site.