Google is being sued for allegedly infringing on search engine personalization patents owned by Personalized User Model (PUM), a Texas partnership based in New York.

The lawsuit was filed on Thursday in a U.S. district court in Delaware.

Google has not yet been served with the lawsuit. Attorney Marc S. Friedman of Sonnenschein Nath & Rosenthal, the law firm representing PUM, said that will happen on Friday.

"Google is being sued for patent infringement for one reason -- it is using PUM's technology and has benefited greatly from it," said Roy Twersky, an owner of PUM and one of the original inventors, in a statement.

Twersky and his co-inventors, Yochai Konig and Michael Berthold, were issued related search patents in 2005 and 2008 covering search personalization. The 2008 patent is an expansion on the 2005 patent, "Automatic, personalized online information and product services."

According to a spokesperson for Sonnenschein Nath & Rosenthal, Google knew about the 2005 PUM patent because a personalization patent that it filed in 2003 was rejected. The 2005 PUM patent, filed in 2000, was being examined at that time. That's why the lawsuit alleges willful infringement, a charge that brings higher damages.

Twersky and Konig now work at a San Francisco-based speech recognition and data mining company called Utopy.

The complaint alleges that Google's iGoogle service, its personalized advertising technology, and personalization features found on Google's Web site infringe on the patents held by PUM.

Friedman characterizes the case as a battle to protect small inventors from big corporations.

For the past few years, Google has been characterizing the patent cases as a something along the lines of highway robbery.

In 2007, Google policy counsel and legislative strategist Johanna Shelton and Michelle Lee, head of patents and patent strategy, said in a blog post that the patent system had not kept pace with the changes in the innovation economy. "Google and other technology companies increasingly face mounting legal costs to defend against frivolous patent claims from parties gaming the system to forestall competition or reap windfall profits," they said.

Friedman acknowledged such concerns and said this isn't just another patent troll case. "In a troll case, you have a situation where someone who is a stranger to the patent files a lawsuit seeking to get a return on investment," he said. "What makes our case substantially different is that PUM has as owners two of the original inventors, including one who himself was instrumental in developing the technology. So this is not a question of a stranger buying up a patent to bring a lawsuit."

Google is likely to object to being asked to produce information about its technology as part of the legal discovery process. But Friedman said courts have procedures for dealing with trade secrets.

Google did not immediately respond to a request for comment.

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