I'm sure that would kick up a lot with PC users... maybe not as much as X-box Live, but still pretty substantial.
In January, Infinity Ward released statistics revealing how many people had played Call of Duty 4 over Xbox Live. It was a lot. Didn't mean much without PS3 stats, though. Which we now have!
While accepting one of the three BAFTAs Call of Duty 4 received earlier in the week, Infinity Ward's Rob Bowling revealed that 11 million people have now been detected playing the game over Xbox Live (that will, of course, include those who have never played multiplayer but were connected while playing). That's 11 million unique users, too.
As for the PS3, Bowling said there have been "over four million" people tracked playing the game over the PlayStation Network. Add those together and you have 15 million people.
Which is an extraordinary number. I mean, there are only 17 million unique Xbox Live accounts. And that's not even counting the PC users, which must also surely number in the millions.