In a session of questions and answers for Fallout: New Vegas in the forums of Bethesda, was told that the game will use Valve Steamworks DRM.

In answer to "The physical version of the PC game will be activated via Steam?" was given the answer: "Yes, Fallout: New Vegas will use to complete the Steamworks SDK."

"This means that the physical PC versions will be activated via Steam. We are also using the Steam for achievements and other characteristics (but not multiplayer. Fallout: New Vegas remains a single player game."

We know.

There's already a big thread on it.

http://www.gamesas.com/index.php?/topic/1096774-best-least-intrusive-experience-for-pc-gamers/

Yep.