I really really like Nihimon's CMO (for the same reasons I disliked his Delta naming! :P).
I think Community Driven Online Game, or CDO (because fully acronym-ized it'd be C-DOG, which is ridiculous) would be the best meshing of the classic 3 lettered "MMO" naming and your Continuous Community Driven Development. It sounds similar enough to an MMO, especially if it's kept at 3 letters but it does at the same time sound too close to a CD.
In the same vein as Pilot Program, how does Concept Test sound? One draws Concept Art as the beginnings of an idea to give it shape and form and a base to work with. The players who're let in at the very beginning will take the Concept Test and give it shape and form as well.
My main concern is that the naming sounds too barebones, as if players'll be playing a skeleton of a game.
(I apologize for the useless, irrelevant eyesore that was my last comment. I need to learn to read more carefully).
I enjoy the trailblazing, frontier-y terminology some of you all have been putting out there, but I especially agree with D'Syndri's "Vanguard" naming because:
1. Using Greek letters/names in no way really differentiates PFO's initial phase as it really should. To most up-to-date PC gamers, naming it PFO Beta or PFO Delta sounds very similar to the nomenclature of every other testing phase every other developer has put out. Naming the Phase after a Greek letter doesn't serve justice to what it sounds like Goblin Works is really trying to do, which is to differentiate whatever GW ends up calling this Phase from what other developers usually call their [Insert Greek Letter] Testing.
2. Using frontier-y language makes it seem like the land is unpeopled, which technically it is, but Lore-wise there are people who have already settled ahead of us and live there who exist in the form of NPCs. Calling it PFO: Genesis or PFO: Frontiers calls up images that we truly are the first, which is somewhat disingenuous (but also somewhat fits I agree, but more on that later).
My support is behind something like "Vanguard Release" as it differentiates the Phase enough from terms like Alpha/Beta Testing and since we're literally invading a virtual space Goblin Works has created. We aren't people who've been retconned into the basic setting from the very beginning but rather the first in a (hopefully) long line of people who'll come to this game, hence we are the Vanguard.
I am in no way trying to bash other's ideas (I know I may come off that way), but basing my ideas off of what you all have written thus far.