More and more games are released these days with DRM technologies to try and control the way games are played. They are viewed as a way to prevent users from playing illegally downloaded copies and also aid in disabling any hacks or exploits (to a lesser extent). About a year ago, Ubisoft caught on with this and started releasing games that were only playable online. In other words, even offline modes required a connection to the internet. Even worse was the fact that the game would malfunction if you lost connection during offline play (e.g. campaigns). The assumption made by Ubisoft was that all gamers had a connection to the internet anyways.
As of today, it appears as if Ubisoft has chosen to disable its “online only” DRM. No official statements were made and things can definitely revert back at any time but it seems like the work of the hoards of fans protesting and posting hacks around this DRM have finally had an effect.