A simple explanation follows.
At its core, BitCoin is unbelievably simple: a ledger of account, no different than an Excel file, distributed across millions of computers, kept honest through offering rewards for protecting the ledger’s integrity. There’s really no such thing as a BitCoin, just a row in that ledger that says “1.23456", and only the holder(s) of the key for that row can send a portion of that number to a different row. Like with any form of money, any value derived from that ledger is purely a product of collective belief.
BitCoin is roughly at the place where Mosaic was in the early 90s. The real story isn’t about BTC becoming the new world currency; it’s a technological and sociological prototype of a new type of distributed application which has only barely begun to be explored.
— lukifer, https://news.ycombinator.com/item?id=7219583