http://www.technologyreview.com/view/518541/rich-get-richer-effect-observed-in-bitcoin-digital-currency-network/"Kondor and pals recreated the network so that each node represents a BitCoin address and drew a link between two nodes if there was at least one transaction between them. They then analysed the way the network has evolved over time."
"Kondor and co say that the network grew by preferential attachment. In other words, a node with a large number of links is likely to attract more links than a node with only a few links."
"This is a well-known effect in network science. Economists call it the Matthew effect after the biblical observation that the rich get richer."
"The Matthew effect is thought to be the origin of the 80:20 distribution of wealth– that 20 per cent of the population own 80 per cent of the wealth."
"Kondor and co say a similar phenomenon is clearly observable in the BitCoin network. Not only are popular nodes likely to attract more links, their wealth is also likely to grow more quickly than less popular nodes."