Note: SE has asked that we NOT do this. See the accepted answer below.
I've been keeping an eye on the questions feed from Server Fault. When I see juicy questions that should be here on NE, I've been commenting and mentioning this NE beta. I've had a couple authors who've then asked for an invite (which I've sent.)
Unless SE generally frowns on this, I suggest that others do this too; See a great NE question on another SE site? ...try to entice the author over here.
Area51 shows that daily traffic is the thing we lack most. (Granted, day three and all. :)