"“With a cellphone, the I.P. address might get you a city or part of a city,” said Jonathan Mayer, a computer scientist and lawyer at Stanford University. “But, if you are using a landline address, that could in fact be incredibly precise — to an exact address or part of a building, depending on how it is configured.”
Mr. Mayer said that his office I.P. address locates him on the fourth floor in a certain section of the Gates Computer Science Building at Stanford."