The hackers have found a way around Ubisoft's DRM.
In the ongoing effort to protect the hard work of the developers, Ubisoft created a DRM scheme that required a constant internet connection for all gameplay, be it single player or multiplayer. Without a constant connection to Ubisoft's master servers, the game cannot be played.
This form of protection caused great inconveniences for buyers of the game, be it on the internet connection end or a takedown of the Ubisoft servers. While the DRM was causing grief for real buyers of the game, it did keep the pirates at bay for far longer than the usual PC game. But the game hackers have finally cracked it.
Cracking group known as Skid Row claims to have created a crack that removes the required internet connectivity from Assassin's Creed II. Some other cracks emulated Ubisoft's servers, fooling the game into thinking it was authenticated. Skid Row, however, said in its nfo notes that its crack cannot be compared to other emulation cracks, as "does not construct any program deviation or any kind of host file paradox solutions."
Skid Row also left a note for Ubisoft, which read, "Thank you Ubisoft, this was quiete [sic] a challenge for us, but nothing stops the leading force from doing what we do. Next time focus on the game and not on the DRM. It was probably horrible for all legit users. We just make their lifes [sic] easier."
While we do not condone piracy in any fashion, solutions such as this one created by hacking groups ensure that Assassin's Creed II will still be playable years from now, or in the event of a connection outage.