I thought it could be played as a single player game or as a MMORPG online. I'm only basing that on what I heard though. If it's true there will be a monthly fee...
[quote name='zewone']Phantasy Star Universe can be played in Story mode or Online mode. There will be a monthly fee. About $9.[/QUOTE]
...for the PC and PS2 versions. There are strong rumors that the 360 version will not carry that monthly fee, thanks to using the Live servers instead of Sega's.