1. An apparatus for identifying potential churning telephony customers, said apparatus comprising: means for obtaining data pertaining to telephone calls between a plurality of customers; means for forming a graph having a plurality of nodes representing said customers and a plurality of edges representing said telephone calls between said customers; means for denoting a sub-set of said customers as previously churned customers; and means for applying a spreading activation model to said graph to identify, based on said graph and said previously churned customers, said potential churning customers, wherein applying said spreading activation model comprises: activating a subset of said nodes of said graph; assigning a spreading factor and a transfer function specifying a fraction of energy transferred by a given one of said subset of said nodes to corresponding neighboring nodes and a distribution of said transferred energy among said neighboring nodes; and ceasing said iterative steps when said subset of activated nodes does not substantially change between successive iterations and when changes in energy between iterations for a given node are less than a predetermined accuracy threshold.