Abstract: A social network marketplace may monitor communications between an advertiser and a consumer by generating signatures for communications and tracking those signatures through social network communications until a sale may be consummated. The marketplace may monitor the transactions to determine a user's influence on other users. A user's influence may also be determined or supplemented by monitoring formal or informal social interactions performed on a computer when those communications are able to be monitored. The influence information may be used to select outbound advertisements to those users who may benefit from an advertisement, as well as to filter inbound advertisements to suit a user or a user's situation.