I made a thread to help people predict this.  Said 6 to 8 PH/s by end of the year.   Honestly I think now it will be closer to 8 to 10 PH/s.  By mid 2014 we probably are looking at 15 PH/s+  if ASIC companies serious cut prices (say <$2 per GH/s delivery in 30 days or less) we could see more than 20 PH/s.   I don't think 30-40 PH/s by end of 2014 is that conservative.   Worst case scenario we way overshoot and end up 50-80 PH/s and new sales flatline for a while.