More generally, in economic aspect, when new currency are issued, and be accepted by groups of people, how will the new currency affect existing currency, ignoring other factors.
Ex. How will BTC affect existing USD?
Ex2. How will LTC affect existing BTC?
Ex3. If a country used to use USD as there currency, but they decide to use a new currency to replace USD, when this currency is becoming more and more important, how will USD be influenced?
It seems that it is more easier to develop new currency for people, not only country, how will BTC find a way out to win the competition with other currency like LTC. What will be the key point in the process?