When you fire up the Tumblr iOS app out of wifi/cellular range it warns you with a red banner featuring the symbol used to indicate the location of fallout shelters in the US in the 60s.
The fallout shelter sign omits the centre circle used as a radiation hazard symbol, in order to represent safety from radiation.
Therefore, technically, it makes some logical sense: it is a lack of a specific kind of radiation that makes Tumblr unavailable. But the combination of the symbol and the red warning banner seems a little incongruous.
But perhaps we’ll soon be recycling the symbol as a warning to network dependent individuals: enter this area and you’ll be cut-off from your information support system.
“Ditch the tech” as they say in that Dollhouse episode.
Aside from the interesting musings on the meaning / choice of the symbol, perhaps this is one for Little Big Details?