NetRatings, Inc. yesterdayfiled a patent infringement lawsuit against The NPD Group. The complaint, filed in the United States District Court for the District of Delaware, alleges that NPD is using
methods for computer use tracking that infringe United States Patent No. 6,115,680, owned by NetRatings. NetRatings is seeking a permanent injunction precluding NPD from infringing the patent, as well
as unspecified monetary damages for past infringements.