Title: Leveraging Social Networks to Fight Spam Abstract: Email communication contains an image of the human social network. Emails sent to multiple recipients have some information about the structure of that network. In this talk I will describe a method of spam filtering based on a network structure embedded in email messages. This approach leverages the fact that email networks are formed by social processes, which have certain signatures which are visible in the graph structure. I will outline how this technique may be used to bootstrap other text classification techniques.