Why? What effect would it have on our lives? To me, most people generally want to see MMO subscription numbers for three reasons:
1) So they can decide if the number of subscriptions is high enough for them to put their time, effort, and money into the game (wouldn't want the game to fail now would we?).
2) If the subscription numbers are low (relatively speaking, of course), they'll be able to spread doomsayer messages about the future of the game.
3) So they can flex their epeen and know they are playing a popular game, thus validating their game choice, which to many MMO players is some kind of lifestyle or second job.
That is really all public subscription numbers do.