1. A method comprising: receiving, at a wireless access point, from a client system of a first user, a request to access a network through the wireless access point, the wireless access point being operated by an entity; sending, by the wireless access point, an identifier comprising a unique code that uniquely identifies the client system to a social-networking system, the social-networking system comprising at least one social graph, the social graph comprising a plurality of nodes and a plurality of edges connecting the nodes, each of the edges between two of the nodes representing a relationship between the nodes, wherein a first node of the plurality of nodes corresponds to the first user; receiving, at the wireless access point, from the social-networking system, a positive authorization determination based on the identifier, wherein the positive authorization is determined because a timeline associated with the first user indicates that the first user has previously checked in with the entity; and providing the client system with access to the network through the wireless access point in accordance with the positive authorization determination.