The game is being shuttered because, "The success of RaiderZ did not meet our expectations and as we saw no other potential alternatives to the discontinuation of the services, unfortunately we were left with no other alternative than to take this step." In response to the announcement, players noted a lack of updates and content surely had some bearing on the lack of interest in the game.
The servers will remain open until August 30th, at which time any players who wish to continue to play the game will have to move to a different publisher (i.e. Perfect World) and start from scratch.
[Thanks to Skurvel for the tip]