Games Radar had a chat with John Carmack about Quake Live:
PC Gamer: What inspired you to resurrect Quake III Arena as Quake Live?
John Carmack: At the very highest level, Quake Live - what we originally called Quake Zero - was one of my experiments about what we could do usefully on the PC platform. The consoles are very good machines for a lot of things, but there are some things the PC platform uniquely does better, such as anything having to do with a web browser and the superior mouse & keyboard interface. [Those things are] pretty darn good reasons to be playing on the PC, and we’re also trying out an innovative business strategy that could pave the way for the future.
Check it out over here. Carmack also made some remarks on why Crysis isn't the future of PC gaming.