Table 1. Aggregation of the iWiW network to a town-level.

	USER-level network	TOWN-level network
Number of NODES	4,078,513	2,558
Number of TIES	336,963,425	1,363,032
Number of intra-town TIES	186,237,393	2,558
Number of inter-town TIES	150,726,032	1,360,474

Data for the user-level network take into account all iWiW links. Data for the town-level network are aggregated: whenever there is at least one user-level link between two persons in different towns there is a link between those towns. As there are always intra-town links, the number of loops in the town network equals with the population of towns.