1. A method, implemented using a computer, of analyzing network traffic related to domain names, comprising: storing network traffic data associated with Domain Name System (DNS) requests for non-existent domains (NXDs); receiving an analysis request associated with at least one domain name; creating, using the computer and based on the stored network traffic data, an NXD list comprising NXDs that received at least one DNS request during a time period; determining, using the computer and based on the stored network traffic data, a similarity metric that reflects a degree of similarity between the stored network traffic of the at least one domain name and the stored network traffic for an NXD listed in the NXD list; and providing an analysis report identifying one or more potentially valuable NXDs based on the similarity metric.