Gravel Rating Systems LLC has kicked off litigation over a “knowledge filter” patent, suing Cellco Partnership d/b/a Verizon Wireless (4:21-cv-00153), Costco (4:21-cv-00149), Deutsche Telekom (T-Mobile) (4:21-cv-00152), Lowe’s (4:21-cv-00150), and Target (4:21-cv-00151), all in the Eastern District of Texas. The defendants are accused of infringement through their respective provision of e-commerce websites, the complaints highlighting features for posting user reviews of products listed for sale. Gravel Rating is part of a raft of related NPEs to launch litigation over the past couple of years—one which, according to public records, continues to grow.