1. A computer-implemented method of supporting targeting of content to users, the method comprising: receiving, from an entity that provides targeted content to users, a request that identifies an IP address of an ISP subscriber; in response to the request, determining whether the IP address can be mapped to subscriber-specific behavioral segmentation data that is specific to, and based on Internet access activity of, said ISP subscriber; when the IP address can be mapped to said subscriber-specific behavioral segmentation data, returning at least the subscriber-specific behavioral segmentation data to said entity in response to the request; and when the IP address cannot be mapped to said subscriber-specific behavioral segmentation data, identifying a geographic region corresponding to the IP address, and returning region-specific segmentation data to the entity in response to the request, said region-specific segmentation data being specific to the geographic region, and not being specific to the ISP subscriber.