Email filter patent puts industry on edge
But is it robust?
A US patent  granted to Postini , the email security company, could grant it legal ownership of a large chunk of the methodology underlying anti-spam and message filtering technology on the market.
The implications for the mail filtering business are huge - if the patent can withstand a legal challenge.
The patent effectively says that any system which intercepts mail, filtering viruses and spam messages from the inbox and then sends what's left to the intended recipient is using Postini's intellectual property (IP). This could apply to a large section of the anti-spam and anti-virus market.
Postini's patent describes using a modified DNS address to redirect email to an email pre-processing service which can "detect and detain unwanted messages such as spam, viruses or other junk email messages". It covers various actions that could be performed on an incoming message, based on a user's settings. These include deletion, forwarding, forwarding of partial messages and mailing to several addresses. It also covers broadcasting the message to one or more wireless devices.
Postini’s founder, Scott Petry, agrees that the remit of the patent is broad, but said that it had to be to cover the work the company had done. He told The Register that the company had filed the patent based on work it considered novel, and that all of it was developed in house. “All our technology is home grown,” he said. “And we protect our IP when we can. If nothing else, this patent will be a good defensive bargaining chip in the event that we get sued for infringing someone else’s IP.”
This is an interesting illustration of the cut-throat world of patenting in the US software business, certainly, but not everyone is convinced the work was novel, even back in 1999 when the patent was filed.
Alyn Hockey, product director at Clearswift , a rival email filtering firm, argues that there is nothing new in the patent, and that if Postini was to seek license fees from Clearswift, the matter would be decided in court: “We have so much prior art on this, it is incredible. There are things in here that are very familiar from other patents I’ve seen in this area.”
Steve Frank, a partner in the patent and intellectual property group of the Boston law firm Testa Hurwitz & Thibeault, told IDG that the patent has many tell-tale signs of weakness: its research section in which the appellants establish originality only cites other patents. According to Frank, this often indicates poor background research, making it more likely that a legal challenge would be successful.
Petry argues that Postini’s job was not to check the validity of its claim, or to find prior art, but to make the claim in the first place. “It may turn out that there are people in the industry whose methods infringe this patent”, he said, but argued that the company did not file the patent to find a loophole to exploit, but to protect the work they had done.
Postini has no immediate plans to try to enforce the patent, but Petry would not speculate about any such activity in the future. ®