CMG (Combine Member Group) was the old name used for non-government factions (called NFG - Non-Faction Group before that).
When switching to the Darkness web-client, the name Faction was used for all official groups.
Bareck, where did you see the term? If it's somewhere on the site it needs replacing, since it's archaic terminology that should no longer be in use.
Of course, if you heard it from another member, some people are just slow to get their heads around change. *shakes his head* You'd think people who are on their computers this much would handle it better.
"May the Grace of Ara go with you, and His Vengeance be wrought upon your enemies."