My theory is that its just sliding down the hill. Soon the forum folk going to be in the water. Save them.
But yeah, I've noticed this. I just think its because there's a lot of activity at SB and the staff need to moderate over there, and most forum members usually follow them over there. If so, I'm not sure why it was at N/Z in the first place, but I definitely remember when N/Z was where all the Kewl Kats hung out.