I wouldn't put that pas EA but I think they can see how many unique players of the who play while logged into PSN XBL. dont developers collect lots of data like this though evrn from single player games (% of players who complete campaing etc)
Sounds like a number plucked from thin air, the sort of thing you'd say to justify Project $10. Dead Space had no online component of any sort, what exactly would EA be tracking? Dead Space 2 locked used copies out of online content, so thats not a useful yardstick either.
What was the figure for Dead Space, 8 unique online players for every unit of the game sold? Something like that.
This industry has a long tradition of outrageous lying unfortunately, from absurdly inflated losses from piracy which amount to thinking of a high number to taking wild guesses at how many owners one copy of a game might have had.