DimDim and Salesforce filed a complaint for declaratory judgment against Richard Williamson [NPE], seeking declaration that its online, web-based collaboration software does not infringe a patent related to distance-learning applications.  Williamson has filed four prior suits since November 2002 against more than 20 defendants, including Adobe, AT&T, Cisco, Citrix, IBM, Microsoft, Salesforce, and Verizon.  Williamson also filed an infringement suit against Salesforce and DimDim in the Central District of California on the same day that this complaint for declaratory judgment was filed against him.  Blackboard filed an action for declaratory judgment against Williamson and At Home Bondholders’ Liquidating Trust on May 20, 2012.  According to the complaint, Salesforce acquired DimDim in January 2011.  The patent-in-suit originated with At Home Corporation, and At Home Bondholders’ Liquidating Trust is listed as the current assignee according to the PTO.  Regarding an earlier suit against AT&T and Verizon, Bloomberg reported that Williamson is the trustee for At Home.  7/2, Northern District of California, assigned to Magistrate Judge Joseph C. Spero, 3:2012cv03403.