Interesting comments on Mac and Linux platforms [1]:

"Other interesting sort of PC-ish platforms, we have... the Mac still remains a viable platform for us. The Mac has never required any charity from id, all of those ports have carried their own weight there; they've been viable business platforms.

I actually think that the Mac is going to become a little bit more important for us. Interestingly, we have a ton of people that use, like Macbooks at the office, but we don't have any really rabid, OS X fanboys at the company that drive us to go ahead and get the native ports out early.

But, one of my pushes on the greater use of static analysis and verification technologies, is I pretty strongly suspect that the Clang LLVM sort of ecosystem that's living on OS X is going to be, I hope, fertile ground for a whole lot of analysis tools and we'll wind up benefiting by moving more of our platform continuously onto OS X just for that ability to take advantage of additional tools there.

Linux is an issue that's taken a lot more currency with Valve announcing Steam for Linux, and that does change, factor, you know, changes things a bit, but we've made two forays into the Linux commercial market, most recently with Quake Live client, and, you know, that platform just hasn't carried its weight compared to the Mac on there. It's great that people are enthusiastic about it, but there's just not nearly as many people that are interested in paying for a game on the platform, and that just seems to be the reality. Valve will probably pull a bunch more people there. I know absolutely nothing about any Valve plans for console, Steam-box stuff on there; I can speculate without violating anything.

One thing that also speaks to the favor of Linux and potential open source things is that the integrated graphics cards are getting better and better, and they really are good enough now. Intel's latest integrated graphics cards are good. The drivers still have issues. They're still certainly not going to blow away somebody's top of the line SLI system, but they are completely competent parts that are delivering pretty good performance.

And one of the wonderful things is that Intel has been completely supportive of open source driver efforts, that they have chipset docs out there, and they work openly with community to develop that, and that's pretty wonderful. I mean, anybody that's a graphics guy, if you program to a graphics API, use D3D or OpenGL, you owe it to yourself at some point to go download the Intel chipset docs. There's hundreds of pages of them, but you really should read through and see what happens at the hardware level. It's not the same architecture that Invida and AMD have on there, but there's a lot of commonalities there. You'll grow as a graphics developer to know what happens down at the bit level.

Another one of those things, if I had more time, if I could go ahead and clone myself a few times, I would love to be involved in working on optimizing the Intel open source drivers there.

So, it's enticing, the thought there that you might have a well-supported, completely open platform that you could deliver content through the Steam ecosystem there. It's a tough sell on there, but Valve gets huge kudos for having the vision for what they did with Steam, sticking through all of it. It's funny talking about Doom 3, where we can remember back in the days when they're like, 'Well, should you ship Doom 3 on Steam, go out there, make a splash?' ... I'm like, 'You're kidding, right?' That made no sense at all at that time, but you know Valve stuck with it and they're in a really enviable position from all of that now.

It still seems, probably crazy to me that they would be doing anything like that, you know, but, it's something that's not technically impossible, but would be really difficult from a market, sort of ecosystems standpoint."

[1] https://www.youtube.com/watch?v=wt-iVFxgFWk#t=44m28s