In 'Preemptive Action,' Blackboard Sues Turnitin Over Patent Dispute

By DAN CARNEVALE

Blackboard Inc. has filed another lawsuit against a company over patent rights. But this time Blackboard does not own the patent in question. It is suing the patent owner to avoid being sued itself -- it's what Blackboard officials say is a "preemptive action."

The patent owner is iParadigms, a company...