With regard to this
Old Topic, the last post dates back to November 2013 and wild guesstimates ranged from 400K to 1 Million.
Anyone wants to take a stab at this?
More importantly, what would it take to put BTC (or another digital currency) in the hands of hundreds of millions of people around the world to use daily?
The number of 0.01BTC, 0.1BTC and 1BTC keys have all grown roughly 1.5x since Nov 1st. I expect that is roughly proportional to a 1.5x increase in the number of users.. however even 400k may still be a high estimate for the number of users who currently control as much as 0.01BTC.