Running some tests on the competing platform, PC Gamer found that some Steam keys (the codes you can use to activate a downloadable copy of a game), for games like Battlefield Bad Company 2, Dragon Age Origins, Mass Effect 2, Dead Space 2, Alice: Madness Returns and Dragon Age 2, worked when you used them on Origin.
That’s a neat touch. You’d expect, given the video game landscape in 2011, that EA would maybe make you buy your games all over again. Or delete vital system registry files out of spite for recognising the presence of Steam. But no, the fact the keys work all over again mean you can not only launch your Steam games from within Origin, but once launched you’ll be able to use Steam functions like in-game overlays.
EA Steam keys can be activated on Origin [PC Gamer]