1. A method comprising, by one or more processors associated with one or more computing devices: maintaining a database of connections between a plurality of members of an online social network; creating, responsive to a new user joining the online social network, a new entry for the new user in the database; determining whether the new user joined the online social network in response to a request from an existing user of the online social network; and if the new user joined the online social network in response to a request from the existing user, then sending a prompt to the new user to confirm the relationship between the new user and the existing user, the prompt comprising a user identifier of the existing user.