We pick b.root-servers.net, one of the 13 root servers (1), and ask it about facebook.de and learn that de is delegated to six name servers (2), so we ask a.nic.de where we learn that facebook.de is delegated to two name servers, including b.ns.facebook.com (3), so we ask that one and get the following answer:
Facebook.de is ranked #157955 world wide and is hosted on a server in Menlo Park, CA, United States even though the hostname implies Germany. It has 10622 inlinks.
The name server b.ns.facebook.com
There are more than two hundred domains that use the name server b.ns.facebook.com.
The two name servers a and b.ns.facebook.com together
Six percent of the more than two hundred domains that use name server group 1 point to the two IP numbers 2a03:2880:2110:df01:face:b00c::8 and 173.252.110.27 together, hereafter referred to as "IP group 1". Worth noting is that eight of the host names that point to IP group 1 use name server group 1.