a method of storing and / or retrieving location - based information comprises : storing , in a distributed network of data storage devices accessible simultaneously from a plurality of remote user terminals , data defining a plurality of first localities in relation to which information storage is accessible , and selecting ones of the first localities to represent second localities for which information is to be stored and / or retrieved such that i ) the first and second localities bear a predetermined locational relationship , and ii ) the first and second localities bear a predetermined relationship in size .