Zillow is suing Trulia for the violation of its Zestimates patent; the syndication site alleges that Trulia's "Trulia Estimate" infringes on its patent.

By Stephanie Sims

Zillow sued Trulia yesterday, alleging that Trulia infringed on its patented technology that valuates properties. This patent, called “Zestimates,” is particularly known on Zillow launching “Trulia Estimates” for public consumption.

Trulia Estimates – Infringing on Zestimates Patent?

According to Agent Genius, Zillow filed for the patent in February of 2006 for Zestimates, and it was granted in June of 2011. Officially titled “U.S. Patent Number 7,970,764” for what Zillow called “Automatically Determining A Current Value For A Real Estate Property, Such As A Home, That Is Tailored To Input From A Human User, Such As Its Owner.”

However, within the lawsuit, reference to Trulia’s recent S-1 filing for IPO status with the U.S. Securitites and Exchange Commission, refers to its “Estimates” tool as an effort to raise $75 million.

In addition to damages, Zillow is seeking a permanent injunction for “Trulia Estimates.”

This is not the first time that patent lawsuits have entered the world of real estate data. Back in May, CoreLogic filed a patent infringement suit against Redfin, alleging that Redfin’s Home Price Tool violated a patent for its own home pricing technology. Also, Trulia itself has been sued before for patent infringement; last fall, CIVIX filed a suit against the website for its database systems, the same lawsuit it had levied against the National Association of Realtors. Trulia, settled the suit last month for a reported $900,000.