1. A method for implementing, at a family tree building system, an interactive display of a family tree with family members and relationships between family members, the method comprising: providing, by one or more computing systems, access by the family tree building system to a data store of information at a social network website corresponding to one or more of a plurality of users of the social network website, the social network website operated at a system separate from the family tree building system that implements the display of a family tree, wherein access to the data store at the social network website is through a user of both the family tree building system and the social network website, wherein that user provides information to the family tree building system in order for the family tree building system to access the separate social network website, and wherein the social network website comprises: a plurality of data nodes, each data node representing data relating to a corresponding one of the plurality of users, and a plurality of edges, each edge defining a connection between a corresponding pair of the nodes; determining, by the one or more computing systems, whether the connection between a first node in the social network website, corresponding to a first user, and any one of a plurality of second nodes in the social network website, corresponding to other users, reflects a possible family relationship; displaying, in an order, user names for the other users corresponding to each of at least some of the second nodes; receiving, from the first user and based on the displayed user names, a selection of at least one of the second nodes as representing a relative; receiving, from the first user, data identifying the family relationship of the relative, represented by each of the selected second nodes; and arranging the first node and the selected second nodes, accessed from the separate social networking website, as arranged nodes in the family tree, with the arranged nodes connected in the family tree according to the family relationship between the arranged nodes.
11. The method of claim 1 , wherein the information provided by a user to the family tree building system in order for the family tree building system to access the separate social network website comprises login information of that user.