As reported by Gamespot (and as duly noted on our forums by alert member higgsboson), UbiSoft has announced it is no longer on board as publisher of The Matrix Online. Warner Bros. and Monolith are still committed to the project, however, and the game is still under development.
At the time of this writing, the official site is up, but the forums (hosted by UbiSoft) are offline for "frequency modification." They are expected to be back online within 24 hours.
The Matrix Online's official site is here.
Monolith's official site is here.