My idea is to work on the USB logo to depict the core idea behind dead drops - to share. Several USB logos are arrayed over a circular path to create the logo, which ultimately appears as a map or as the central source from which all information diverges (or converges).

Update 1: Ok, have simplified a lot. Removed an absolutely literal USB reference, though the lines remain. Have also tried a different orientation for the icon and a more complementing typeface. The coloured dot in the centre is to signify the origin of the data and also to break the monotony of all black with a contrast.

Update 2: The USB symbol details are back! I agree, thats the crux of the idea so its totally lost in concept without it.