I added a new line of functions to serversniff: Reports. Currently there are NS-Reports, AS-Reports and, new today, Domainreports.
While the domain-report is still under heavy development i feel like its just perfect for visualizing the host- and network-structure of a domain. Try it out with stuff like http://serversniff.de/dnr-norge.no. You can easily identify external hosts or specialized routing. Try it out and have fun and insights.