Phantasy Star Online 2 is coming out eventually, isn't it? Not that surprised. Maybe some hackers somewhere can setup a private PSU server for those really dedicated people, I mean the original PSO still has those private servers last I checked.
Considering how SEGA have been treating this game for the last two years with the lack of the content that they were really promising: I'm not too surprised that the servers are shutting down. If you like PSU, I would recommend playing on the superior Japanese servers that have a surprisingly active English community and are close to two years ahead in updates. It's free to play too.
So...The Japanese PC servers went down on the 27th effectively ending all official online portions of Phantasy Star Universe. Xbox 360 had Episodes 1 and 2 (AOTI) as well as PC (though I'm told you needed an online connection to play AOTI on PC) which means the only way to experience Episode 2 is now on the Playstation 2 since you could play it offline. Episode 3 however is now lost forever as that was online only.
Not necessarily forever. There is an open source PSU server, written in a terrible programming language: https://github.com/essen/egs Provided they have dumps of the quests, they can probably be restored at some point. I would expect that they probably planned for this in advance and prepare accordingly, since the server was in development long before the servers went down.