This system tracks domains which resolve to IP addresses with an unusually high distribution across autonomous systems (ASNs) i.e. IP address block owners. This alone is not an indicator of Fast Flux domains, which are categorised as resolving to a constantly changing set of IP addresses, i.e. a bot net. The history view shows how the total number of IPs and their associated ASNs changes over time given frequent domain resolutions.
Domains which have been observed to resolve to the same IP address are classed as being part of the same Network Family. The degree to which the IPs resolved from one domain appear in the resolutions from another domain can be seen in the Venn diagram.