A difficult concept to wrap your head around is that a bitcoin can be divided into ever smaller units as needed, so it remains usable no matter how large the population becomes. Even with a global population of a trillion people on Earth, anyone can send or receive amounts of any size because the unit itself can be split further and further, and further. 0.0000000001 bitcoins The software could retain precision that its interface did not display. Satoshi Nakamoto discouraged developers from relying on those extra displayed digits: 
“I would not encourage using the extra decimal places. They’re only intended for future use.” 
He explained that a recipient would see the amount rounded down in the interface. This concerned precision beyond the client’s two displayed decimal places, not an extension beyond Bitcoin’s eight-decimal accounting. Since this post by Satoshi on September 23rd, 2010, the price of bitcoin has increased exponentially and many people now use additional decimal places.