[ZeroSolstice]

Realistically though what information can you glean from a hosts IPv6 address that wouldn't already be part of WHOIS? With IPv4 you already know there are only (3) rfc1918 reserved ranges. Anyone can use them as they see fit so seeing a 10/8 address in a email header doesn't automatically mean the company is huge its just what they picked. Myself, i've just never really bought into the whole "dns naming" or discovering private address ranges giving anything away. With existing NAT device tracking moved onto more unique features such as browser, screen size, etc. such that IP address tracking is probably not as accurate.