Do we even know? Originally it was supposed to be 666x3 per continent, but it obviously ain't that now. All I see, night after night, even after spending ten minutes in the queue so I can squeeze in, is one raging-*** main fight and another medium-sized one elsewhere, tops. And neither seems any larger than the battles we were fighting ten years ago. We had some three-way red alerts that *dwarf* anything I've seen in PS2. Obviously the technology isn't quite there yet to allow for Higby's 'hundreds of players fighting hundreds of players in giant clusterfudge battles.' That's gone by the wayside. So what's the real world figure now? Do we know? My sense is it's something like 250 per. empire.
I have always heard these numbers. I have nothing to prove they are correct, just what I have seen quoted many times. 2000 players per continent with 666 per faction. (I know that only makes 1998 players). So that would make 6000 player servers with 2000 per faction on the server.