Relevant content is prepared and selected for delivery to a member of a network based, in part, on prior online activities of the other members of the network, and the closeness of the member's relationship with the other members of the network. The relevant content may be an online ad, and is selected from a number of candidate online ads based on click-through rates of groups that are predefined with respect to the member and with respect to certain attributes. An online ad's revenue-generating potential may be considered in the selection process.