Beginning with the release of RUSE, Ubisoft curbed the use of its atrociously executed antipiracy safeguards, which required a constant internet connection for the game to function. Apparently, an online connection is now only required at startup.
PC Gamer reports that the constant DRM checks on games like Assassin's Creed 2 and Splinter Cell: Conviction have ceased. They'll only be required at startup - not throughout the game. If an online connection is lost mid-game, it will still continue.
Earlier this year, hackers wrought havoc against Ubisoft shortly after its hated policy came to light, shutting down Ubi DRM servers and freezing PC gamers out of titles they'd bought, whether they were playing them online or not. Ubisoft responded with free game downloads for those shut out of the games.