The picture above is an example of how warchalking might look like. Maybe not something that you understand instantly, but if you go over to Everything Burns and look at the proposal there, you might get a better idea of what it means.
Starting in London, people are marking WiFi spots in chalk on the street, called Warchalking. Just like the hobos of old, these WiBos(Wi-Fi Hobos) are marking places friendly to them. They are using take-offs of the hobo sign system to mark places where bandwidth is available
[Via Sifry’s Alerts]