The Navy Marine Corps Intranet appears to be simply the Navy Intranet or the Marine Corps Intranet depending on what side of the Pentagon you salute. Navy users can plow through literally thousands of E-mail addresses in the MS Outlook global address book without seeing a single Marine Corps E-mail address. Marine Corps users have no access to the Navy address list either.
NMCI has stated that it has "no plans" to merge the two databases. We believe that is perhaps a bit overstated (and certainly came from an unofficial and non-authoritative source). Perhaps they mean they have no immediate plans to provide a single address list. Perhaps they can not do it because of technical limitations in their chosen database method.
Whatever the reason, the purple color of NMCI appears to be fading a bit more every day.