An anti-spam patent granted to Postini could cause problems in the managed e-mail market, experts have warned.

If enforced, the patent, which covers an e-mail "pre-processing service" could grant Postini legal ownership of a wide range of anti-spam and e-mail security methods. However, some industry experts doubt that the patent, filed in September 2000, will stand up to legal scrutiny.

Patent no.6,650,890 was awarded to Postini by the US Patent and Trademark Office in November 2003. The patent cites three inventors, including Postini co-founder Scott Petry and former employee Gordon Irlam. It describes a variety of methods for providing messaging services in an e-mail network.

Among other things, the patent covers the use of an "intermediate pre-processing service (in) the electronic message delivery path" that requires changing the "Domain Name Server entry ... of the destination email server to contain an IP (Internet Protocol) address of the intermediate pre-processing service."

Different methods of message "pre-processing" are addressed in the patent, including forwarding based on instructions stored in user profiles, forwarding parts of the e-mail message content, forwarding e-mail to wireless devices, junk e-mail filtering, and virus detection, according to the patent.

Companies like Postini, MessageLabs, MX Logic and Frontbridge Technologies intercept inbound e-mail on behalf of their customers, then filter out spam, viruses and other unsuitable messages before sending the remaining e-mail messages on.

The patent declares such configurations as Postini's intellectual property, said Steve Frank, a partner in the patent and intellectual property group of the law firm Testa Hurwitz & Thibeault. "To the extent that Postini's competition is running pre-processing centers that intercept e-mail and does something to it, this patent has fairly broad coverage," Frank said.

Postini executives are studying the patent and considering ways to "maximise" its value to the company. In the meantime, customers and potential customers should have more confidence that the company's technology is built on a solid legal footing, said Shinya Akamine, president and CEO of Postini.

However, legal experts said that Postini's patent has tell-tale signs of weakness and may not stand up to legal challenges, should competitors decide to fight the patent award. Postini's patent only cites other patents in the crucial "References" section that is used to establish the originality of the patented technology compared with prior inventions, also known as "prior art".

The lack of non-patent sources of information often indicates loose background research by the patent owners prior to filing, said Frank and Greg Aharonian, publisher of the Internet Patent News Service and a critic of USPTO work on software patents.

Frequently, the best prior literature from which patentability is questioned is from non-patent documents that can be found online, or at a university library, such as proceedings from the Institute of Electrical and Electronics Engineers(IEEE) or magazine articles, Frank said.

The lack of solid research behind the Postini patent is just an example of "major abuse" of the patent system by applicants and attorneys, who hope to slip patents by the USPTO, Aharonian said. "All the applicants know examiners don't have the resources to search down this stuff. At most they can search prior patents because it's all online at the (USPTO). But their physical library of journals and books is borderline non-existent," he said.

Competitors, including MessageLabs and United Messaging, now Bluestar Solutions, should have an easy time demonstrating that they were selling a service similar to Postini's before the company filed for its patent, said John Levine of the Internet Research Task Force's Anti-Spam Research Group. "If MessageLabs wanted to bust this patent, they almost certainly could," he said.

In an e-mail statement attributed to MessageLabs president Jos White, the company said that it has a policy of respecting the valid patent rights of others. However, White also noted that MessageLabs "pioneered the managed services model for e-mail security, launching the first Internet-level e-mail scanning service in 1998 (as part of Star Internet, now our sister company)."

Regardless of whether the patent is ultimately upheld, it can be an effective tool against competition, Aharonian said. "Litigation is an effective harassment tool. Once a patent is issued, it's assumed to be valid, so Postini can be as obnoxious as they want about enforcing the patent and not be worried about getting sanctioned by the courts," he said.

The effect of the patent on the growing anti-spam community depends on how hard Postini tries to enforce it, Levine said. Patent disputes are often very technical and take a long time to be heard and resolved, which can give companies like Postini breathing room. Also, weak patents can be upheld, he said. "It's like rolling a gigantic pair of dice," he said.