I haven't seen Xerxes' posts in a long time, come to mention it....
I was pming him few times awhile back, but that was like couple of months ago if I remember correctly, and I'm just speculating but I think he finally got off here. He's found peace and is occupying his mind with little easyer on the mind stuff. And with all the internet spying/censorship rising it's not such a bad idea. In the future people are gonna hve their own identity card just o use the net at all.
If one goes, one goes and no good byes are needed. Xerxes is smart enough to do that and perhaps he did.
I hope he will live his life well!