I like the idea of 'retired' signs and sometimes show them on my Flickr stream. One of the good things about Scollon and Scollon's 'Discourses in Place' is the detailed attention given to the context of everyday environmental signs. They suggest that 'there is a major aspect of [...]meaning that is produced only through the placement of that sign in the real world in contiguity with other objects in that world.' (Scollon & Scollon, 2003:30). But of course place cannot be properly discussed without time. This No Parking sign has, I assume, lost its authority through the passage of time. How do we know that a sign's meaning is still current?