What do you mean by "Ranking system"? Are you looking for strictly PvP in the Street Fighter style? Or are you looking for a game like Streets of Rage which has mostly PvE?
I don't know how "Massively" Multiplayer an arena style fighting game can be, but I know the Soul Calibur titles allow very in-depth customization, online play, and rankings.
I don't play consoles anymore, but a friend of mine loves the online aspects of those games.
EDIT: D'oh.. you said 2D. Well, there's also the option of downloading emulators or searching for groups that emulate on that built-in client that allows users to connect via TCP/IP (starts with a K I think). Off-hand, I don't know of any 2D pvp fighters in the style you're looking for that are advertised as MMO's though. MMOHut lists 2D non-RPG MMOs on their front page.
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I don't know how "Massively" Multiplayer an arena style fighting game can be, but I know the Soul Calibur titles allow very in-depth customization, online play, and rankings.
I don't play consoles anymore, but a friend of mine loves the online aspects of those games.
EDIT: D'oh.. you said 2D. Well, there's also the option of downloading emulators or searching for groups that emulate on that built-in client that allows users to connect via TCP/IP (starts with a K I think). Off-hand, I don't know of any 2D pvp fighters in the style you're looking for that are advertised as MMO's though. MMOHut lists 2D non-RPG MMOs on their front page.