The Illumos Project is an actively worked Open Source project based upon OpenSolaris from Sun (now Oracle) using external contributors. Illumos was announced publicly on Aug 3, 2010, 1PM, EDT via a conference call. The announcement was also made physically at the Chrysler Building, NYC.

Community Support
[http] Illumos Documentation (online & github)
[http] Illumos Community Mailing Lists & Support Forums
[http] Illumos IRC Channels

Illumos Reference Material
[http] Illumos FAQ (Frequently Asked Questions)
[http] Illumos IssueTracker
[http] Illumos Projects

Illumos Based Distributions
(SPARC & Proprietary Intel)
[http] Tribblix
[http] DilOS
[http] MilaX / v9os
(Proprietary Intel only)
[http] OpenIndiana
[http] SmartOS
[http] NexentaStor
[http] StormOS
[http] OmniOS
[http] Illumian