Bitcoin is a new kind of global payment network. Like MasterCard or PayPal, it allows money to be transmitted electronically. But Bitcoin is different from these conventional payment networks in two important ways.

First, the Bitcoin network is fully decentralized. The MasterCard network is owned and operated by MasterCard Inc. But there is no Bitcoin Inc. Instead, thousands of computers around the world process Bitcoin transactions in a peer-to-peer fashion.

Second, MasterCard and PayPal payments are based on conventional currencies such as the US dollar. In contrast, the Bitcoin network has its own unit of value, which is called the bitcoin. The value of one bitcoin fluctuates against other currencies in the same way the euro’s value fluctuates against the dollar. In November 2015, one bitcoin is worth around $400, and all bitcoins in existence are worth around $6 billion.

In 2013, the skyrocketing value of Bitcoins — from $13 in January to more than $1,000 in early December — pushed it into the mainstream. Venture capitalists invested $95 million in Bitcoin-based startups in 2013, $347 million in 2014, and more than $450 million so far in 2015.

But there hasn’t been much sign that Bitcoin is revolutionizing the financial industry the way optimists hoped it would three years ago. Use of the Bitcoin network has grown only slowly. Almost seven years after the network was created, there still aren’t any good examples of Bitcoin applications that are accessible and useful to mainstream users.