Methods and arrangements for constructing and analyzing federated social networks. A first social network with a first plurality of accounts is defined, as well as a second social network with a second plurality of accounts, the second social network being unaffiliated with the second social network. The first and second social networks are federated to determine a union of the first and second social networks and an intersection of the first and second social networks, and second-order connections between one or more of the first plurality of accounts and one or more of the second plurality of accounts are ascertained, the second-order connections including connections outside of the intersection of the first and second social networks and within the union of the first and second social networks.