CVG has published
a short interview with BioWare's Ray Muzyka about the PC version of Mass Effect, Sonic: The Dark Brotherhood, and the possibility of future downloadable content for all of their games.
DLC - any plans for more after Sky?
Muzyka: Oh yeah, we have big plans for post-release content with the franchise for both Xbox 360 and PC. We haven't released any details on that yet but it's something we want to actively support.
So no hints on when the next lot will come?
Muzyka: You know, it's all about the quality. We want to make sure it's a really great experience; and we also want to do different things, we like experimenting and trying different things for post-release content.
We did a lot of post-release content with Neverwinter Nights, we're planning to do more on Dragon Age in the future as well and Mass Effect and other products we have in development.
We just want to make sure we're satisfying what the fans want first, so often it's good to get their feedback and say, "What kinds of things would really be exciting to you?", and how can we put those in the game.
Mass Effect Interview 
Linear Mode
