Mistakes in 1st paragraph
Like OP quoted also :
"Bitcoin is a virtual currency, or “cryptocurrency”, that first appeared on the radar in 2009 after an anonymous creator “buried” 21 million coins online."
...
So far as I know Bitcoin is a Digital Currency not a Virtual Currency...
http://en.wikipedia.org/wiki/VirtualityVirtual currency are coins from Second Life
Bitcoin is not a Virtual Currency ...
Although its status as a currency is disputed, media reports often refer to bitcoin as a cryptocurrency or digital currency.