BioWare title 'will require' one-time authorisation through Origin

Mass Effect 3 will not be available through Steam, EA has confirmed.
The publisher revealed that the latest sequel in the blockbuster Sci-Fi franchise would not be on Valve's digital distribution platform due to what it claims are a “set of restrictive terms of service” limiting how developers can interact with customers.

The game will instead require users of both the retail and digital PC versions to download EA's own e-store Origin to access the game.
“During initial release Mass Effect 3 will be available on Origin and a number of other 3rd party digital retailers, but not on Steam at this time,” said BioWare community manager Chris Priestly.
“Steam has adopted a set of restrictive terms of service which limit how developers interact with customers to deliver patches and other downloadable content.