I just become aware of Bitcoin this week watching "Security Now" at Twit.tv. The main question I have about the system is why was 21 million bitcoins selected as the final cap?  Why not something more "round" like 100 million or 1 billion?  And why such a relatively small number?  I understand about the 8 decimal places giving you essentially 2.1 quadrillion tradeable units.  But the general public is not used to dealing with more than 2 decimal places in their currency. If the system took off to even the size of PayPal alone, a single bitcoin is going to be worth some huge number and we're all going to be buying things priced at inconvenient amounts like 0.00023, etc., right?