Agreed that the Log(Log) graph fits recent data better, however there is no principle behind the equation as there is with a logistic model of population growth with resource constraints.  The Log(Log) model suggests that prices during 2014 will reach 100000 USD by summer 2014. To me, this is not a plausible growth rate for bitcoin prices.

I believe that 2012 simply under performed and that 2013 over performed with regard to the log trend line.