1. A method comprising: by one or more computing devices associated with a social-networking system, receiving from an initiating user a request for contact information of a target user; by one or more computing devices associated with the social-networking system, determining that one or more privacy settings of the target user prevent the contact information of the target user from being provided to the initiating user; by one or more computing devices associated with the social-networking system, determining that the privacy settings allow for an anonymous communication session between the initiating user and the target user; by one or more computing devices associated with the social-networking system, establishing the anonymous communication session between the initiating and target users, wherein contact information of the initiating user is presented to the target user in the anonymous communication session and contact information of the target user is hidden from the initiating user in the anonymous communication session; by one or more computing devices associated with the social-networking system, in response to the anonymous communication session ending, providing an automatic prompt to the target user to: create a social-networking relationship with the initiating user in the social-networking system; or block the initiating user from the target user in the social-networking system; and by one or more computing devices associated with the social-networking system, in response to input from the target user responsive to the automatic prompt: creating the social-networking relationship between the initiating and target users in the social-networking system; or blocking the initiating user from the target user in the social-networking system.