The notorious U.S. patent 6,411,947, a broad "method" for automatically classifying and responding to email inquiries known as the Firepond/Polaris patent, has finally been invalidated after 12 years on the books.

The patent was on the Electronic Frontier Foundation's list of top ten most bogus patents because it claimed nothing more than a system using natural language processing to select and send responses to customers' online or email inquires.

The drawing that accompanied the now-invalidated patent:

Patent owner Polaris/Bright Response LLC had successfully invoked the patent in 2006, suing Kana Software, Sirius Satellite Radio, Priceline, Capital One, Continental Airlines and E*Trade and settling for undisclosed terms.

A year later the company sued AOL, Google, Yahoo!, Borders, Amazon, and others for infringing 6,411,947, which claims automated email message classification using "a combination of a case base knowledge engine and rule base."

The company was widely criticized for attempting to extract money from its questionable patent.

"It looks like Polaris IP is in the business of licensing patent rights and has no desire to enforce its requested injunction," Dennis Crouch, associate professor of law at University of Missouri School of Law and the author of the law blog Patently-O, told Information Week. "I expect that Polaris IP will be willing to settle these cases for what it believes is a reasonable six- or seven-digit figure."

A jury in the Eastern District of Texas found three of the patent's claims invalid based on the public use bar (method is already in public use at the time of filing), obviousness, and for lacking written description. The jury also found that neither Google nor Yahoo! infringed those claims.

Finally, the jury found the entire patent invalid due to improper inventorship. Nine of the EFF's top ten most bogus patents have been invalidated or are being re-examined.

The abstract describing the now-invalid patent for "Automatic message interpretation and routing system:"

A method for automatically interpreting an electronic message, including the steps of (a) receiving the electronic message from a source; (b) interpreting the electronic message using a rule base and case base knowledge engine; and (c) classifying the electronic message as at least one of (i) being able to be responded to automatically; and (ii) requiring assistance from a human operator. The method for automatically interpreting an electronic message may also include the step of retrieving one or more predetermined responses corresponding to the interpretation of the electronic message from a repository for automatic delivery to the source.

What do you think? Patentable? Or total sham?