It's very exciting!!
It means the Source engine gets OpenGL support. This also means it would be much more easy to port it to Linux!

They look like they still only have one button but infact they have 4. You just left and right click as normal and the scroll button is button 3 and then you have buttons on either side. Tbh if they're going to do that then make a normal mouse ffs!!!

I still think it's one of their trademarks, but I know there are "normal" mouses as well for Mac, or so I've heard

lol dont have a goooo anna! i had to use a mac at uni and it was bloody rubbish! and only had one mouse button.,

You could just hook up your "regular" mouse, y'know.

EDIT: Is that Bam in the bottom left?

Crass you are amazing and this is really a great find +Rep for you and I suggest you all do the same and give him his credit.

Valve and Epic Games might have just kicked off a match made in violent games heaven. According to GameSpy "revealed a partnership with Epic Games that will make the Steamworks suite of publishing and development tools free to all licensees of Epic's Unreal Engine 3." this includes a rather impressive list of publishers using Unreal Engine 3 licenses such as Activision, EA, 2K Games, THQ, Ubisoft, and Square Enix.

Here is what Epic's Mark Rein had to say about this new deal.

"With Valve offering these services free of charge, the idea of providing the Steamworks SDK to all Unreal Engine licensees was a no-brainer."

Valve's Gabe Newell also chimed in with a few positive comments of his own.

"Epic's technology is one of the most widely used engines in the industry and has powered many of the best games created in the past 10 years, on multiple platforms. It's an honor to have Steamworks included in the technology offered to all Unreal Engine 3 licensees. It's hard to think of a larger, better targeted group of developers who could derive more benefit from the Steamworks services."

To be clear, this means that future Unreal Engine 3 titles appearing on Steam will have a higher chance of incorporating Steamworks features (achievements, Steam Cloud, etc.) into the game. There is no guarantee that all future UE3 titles will make use of this new integration, but the chances that they will just went up dramatically.

We will undoubtedly have more details about this partnership as time goes on. Stay tuned!