This Is Litecoin, The 'Silver' to Bitcoin's 'Gold'
As I mentioned, there's absolutely no reason to have just one. In fact, more is better, up to some point. Also, they're demonstrating that monetary supply policy is a totally configurable feature. Eventually one of these guys is going to realize that there's no real reason to "cap" the total supply at all. A modest ongoing inflation rate can be a good thing, a la Krgthulu.
Bitcoin isn't the only cryptocurrency out there.
An alternative called Litecoin is starting to gain traction.
Bitcoin and Litecoin are incredibly similar. Both are decentralized electronic currency, meaning that they aren't linked in any way to big banks. They're independent. And where the money supply of US dollars is always fluctuating, both Bitcoin and Litecoin will reach eventually reach a gross sum and maintain a finite, unchanging supply.
Circulation of Bitcoins will be capped at 21 million, Litecoin at 84 million.
Think of Litecoin as the silver to Bitcoin's gold. Just like in the physical silver and gold markets, Litecoin is trading at less than Bitcoin, but there's more of it.
http://www.sfgate.com/technology/businessinsider/article/This-Is-Litecoin-The-Silver-to-Bitcoin-s-Gold-4598910.php