Philadelphia, Pennsylvania recently caught the attention of the hacktivist collective Anonymous when the city government targeted a businessman’s attempt to clean up downtown trash. The city owns a vacant lot overrun with weeds and debris, adjacent to Ori Feibush’s coffeeshop. After years of battling with the city over the eyesore, Feibush took it upon himself to clean it up. He spent at least $20,000 of his own money to remove 40 tons of trash and renovate the property — a project Anonymous claims would have cost Philadelphia taxpayers $1.5 million. The city is threatening Feibush with legal action for trespassing...