Phantasy Star Online players confused about the game's extended downtime over the last week or so have finally been given an answer by Sonic Team. Apparently a rather malicious internet worm that has knackered a whole bunch of other sites and services made its way to PSO's servers as well, so the developer took the action of taking things offline to fix it.
According to PSO World, it doesn't look like the worm impacted anyone's player accounts in a negative way. Just made things super wonky and annoying for those trying to enjoy the game. This, from PSO World:
"Upon investigation into the matter, Sonic Team has concluded that it was indeed the internet worm that affected networks worldwide that caused the massive server down time. Investigating the problem while the servers were up would have been too difficult. Therefore, because of all the confusion, Sonic Team had to take down all the servers to investigate and fix the problem. The servers have since then been restored and have been performing normally since the restoration.
They also apologize profusely for the problem and are sorry for all the problems caused."