CM's own blog is unreachable now, but XDA-Developers already summed it up and clarified some important bits:
- All monetary and infrastructural support for CyanogenMod from Cyanogen Inc. will cease. -> CyanogenMod will no longer receive nightly builds after December 31st... unless the team finds another host to build nightlies.
- CyanogenMod will rebrand as LineageOS.
- The CyanogenMod team will not continue official development on the CyanogenMod project, but the work will continue in LineageOS.
Since it's clear that Cyngn is going in a new direction, Cyanogen OS will almost certainly have no future - it's not community-driven in the first place. CyanogenMod, on the other hand, will live a bit longer, until Lineage truly dawns (or fails).
UPDATE Dec 29, 2016: The GitHub repo and Gerrit code review platform of LineageOS are online, and I have personally verified that codes are fully buildable, and previous CM users can seamlessly transition to current builds. Also, from what the Gerrit shows, the team is now working on renaming all CM elements to Lineage/LineageOS, amongst the usual bug fixes and improvements.
UPDATE Jan 13, 2017: Rebadging is almost complete: LineageOS 14.1 now has a redesigned setup wizard with no CyanogenMod presence. LineageOS 13 remains mostly untouched, since Marshmallow is near deprecation. The download site itself is also accessible, though building has yet to begin.
UPDATE Jan 18, 2017: LineageOS now has its own bootanimation, thus rebadging can be deemed as completed.
UPDATE Jan 23, 2017: All systems operational, and first official builds have rolled out!