War Chalking is marking a building or sidewalk to note the type of WiFi available. In modern times this is not very common, but in the early days of WiFi this practice was used by malicious users to find unsecure wireless networks.
Warchalking is the drawing of symbols in public places to advertise an open Wi-Fi network.
Inspired by hobo symbols, the warchalking marks were conceived by a group of friends in June 2002 and publicised by Matt Jones who designed the set of icons and produced a downloadable document containing them. Within days of Jones publishing a blog entry about warchalking, articles appeared in dozens of publications and stories appeared on several major television news programs around …