thumb|Warchalking symbols
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 published 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 the world.
There is a difference between wardriving and warchalking. Warchalking and wardriving both are used to share information about wireless networks. Warchalking is different from wardriving since warchalking involves marking public spaces with symbols indicating different types of Wi-Fi networks. Warchalking relies on visual cues, while wardriving involves driving around with a device to detect wireless access points. It is a method used to search for networks.
thumb|A warchalking sign on a street in [[Bamberg, Germany]]
Having found a Wi-Fi node, the warchalker draws a special symbol on a nearby object, such as a wall, the pavement, or a lamp post.