Warchalking

No these alien like symbols appearing around cities on the sides of buildings and on the backs of street signs weren't left by space aliens or juveniles as gang tags. They're in fact left by geek wardrivers to mark wireless internet connection points and wireless local area networks owned by individuals and corporations. In some cases these wireless access points were specifically set up and provided for public use but in most cases they were never intended for that purpose.

It turns out there are large groups of geeks all across the country mapping entire cities to identify wireless access points which are working with others who then mark the warchalk symbols around town to point out the access points to others. The symbols have been noticed all around major cities like New York, Pittsburgh, Boston, Miami, San Fransisco and even smaller cities like here in Burlington, Vermont.

Unfortunately the act of warchalking may not be as innocent as it sounds as these vulnerable LANs may also be used by hackers (and maybe even terrorists.) In 'another time' warchalking would be beneficial and legitimate however in these times it's potential to be used by terrorists and others who wish to disrupt network security make it a dangerous practice.

I'll be wiping off any war chalks I see and I suggest you do the same.