The whole BlackBerry system seems to be back up and running now. But it's kind of like an old quarterback with gimpy knees returning from his fifth concussion: still works but is kind of wobbly and no one seems too comfortable using him as a starter any more. Bloomberg reports that BlackBerry owners overseas lost access from Monday through Wednesday but that in North America it was mostly just on Wednesday. Bloomberg says it's possible that MOST BlackBerrys were affected.
It'll be interesting to see what happens here. It will likely affect individual sales. But business users tend to look bigger picture and BlackBerry still has the most secure messaging system in the world. My hunch is that this doesn't kill BlackBerry but just makes it a lot more niche.