Cryptocurrency exchanges are vitally important to the growth of digital currency. Exchanges allow market participants to buy or sell coins for other currencies including US dollar and Euros as well as other types of altcoins. Each coin needs to have a network to allow the free exchange of their currency. Once you have a facility to buy and sell coins, there are ways to make profit. You can use exchanges to speculate on coin prices using margin trading and you can also arbitrage between the various exchange around the world allowing a speculator to capitalize on difference in price between these exchanges around the globe. Using margin trading or arbitrage there are ways to earn profit from the exchange of bitcoin and altcoin.