From a review of the german GameStar
Wie Assassin’s Creed 2 verwendet auch
Ubisoft allerdings leicht entschärft
hat. So müssen Sie beim Klettern und
Meucheln nicht mehr online bleiben,
nach der ersten Internet-Aktivierung
läuft das Spiel auch im Offline-Modus.
And from Gamespot
There are a number of key differences
between Assassin's Creed II and its
follow-up, Assassin's Creed:
Brotherhood, but if there's one that
some PC enthusiasts will appreciate
the most, it's that Ubisoft's
stringent copy-protection scheme has
And from StrategyInformer
Fortunately, Ubisoft has seen sense
this time around, and although certain
security elements are present, it's
barely noticeable anymore and
definitely doesn't feel as intrusive.
The game requires a one-time
activation to begin with, but after
that you can play the single player
offline whenever you desire. The
multiplayer requires you have a
connection (duuh) and some of the DLC
does too, but that's it.
This seems to indicate that there is still an online activation needed, but that afterwards no online connection is needed anymore. So you don't seem to need a permanent internet connection to be able to play the game.