Online play is official now.
The game consists of 3 major parts concerning online gameplay
Story Part
Live Part
Quest Part
The Story Part and Live Part are seamless and a Town Square is mentioned. Speculation here, but my guess is when you enter a city, you get transferred to a server or what not. Up to 16 avatars (players) can be in any given Town Square. From there, you can party up with up to 4 players to go questing and what not. Items can also be traded between players, though details aren't available yet.
http://videogamerx.gamedonga.co.kr/zbxe/files/attach/images/699943/379/998/02.jpg
http://videogamerx.gamedonga.co.kr/zbxe/files/attach/images/699943/379/998/01.jpg
