Real estate technology firm Listingbook LLC has filed a lawsuit against real estate marketing software company Market Leader Inc., alleging Market Leader's customer relationship management platform infringes on a patent awarded to Listingbook's founders. Listingbook announced the suit just a week after Market Leader settled three investor lawsuits related to its pending sale to Trulia. In the complaint, filed July 18 in the U.S. District Court of the Middle District of North Carolina, Greensboro, N.C.-based Listingbook alleges that Market Leader's customer relationship management platform directly infringes on U.S. Patent 7,454,355, titled "Method and system for providing real estate information using a computer network, such as the Internet," filed by Listingbook founders Bob...