Richard A. Williamson [NPE] filed suit against DimDim and Salesforce over a patent related to distance-learning applications.  The complaint is currently unavailable.  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.  Blackboard filed an action for declaratory judgment against Williamson and At Home Bondholders’ Liquidating Trust on May 20, 2012.  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, Central District of California, assigned to Judge George H. King and referred to Magistrate Judge Carla Woehrle, 2:2012cv05701.