Bitcoin

Bitcoin is an "alternative currency" that is generated electronically with no central authority, with a loosely-connected set of network nodes engaged in "mining" coins by being the first to solve difficult mathematical computations, validating transactions involving the "coins" (the process of validating others' transactions is in fact the manner in which coins are "mined", thus incentivizing using one's computer resources to facilitate this process), and storing transactions involving them. This is all accomplished algorithmically. The algorithms are defined such that the rate of coin issuance declines over the years until it tops out at a total money supply of 21 million bitcoins, unlike fiat currencies that can be issued without limit by their issuing authority.

A bitcoin, and its associated transactions, can be represented in various ways, even including actual physical metal coins if you can believe the picture in the Wikipedia article. A binary format is defined in the Bitcoin technical specs, but archived Bitcoin blocks in the "Block Explorer" site are displayed in a JSON-based format (served as text/plain).

The smallest possible unit in a Bitcoin transaction is .00000001 bitcoins, also known as a satoshi. Other subdivisions of the bitcoin are unsettled at the moment, but a unit of 1/1000 of a bitcoin (known as an mbit, or embit, or mBTC) seems to be emerging as rising prices make the bitcoin itself unwieldily large.

There have been attempts to use Bitcoin protocols to implement other decentralized services. Twister is an implementation of a Twitter-like service along these lines, and Bitcloud is an attempt to provide all sorts of cloud-based services this way. Some other attempts at competing "digital currencies" have also been launched with similar mechanisms and varying degrees of seriousness, including Dogecoin and Coinye.

Data format info

 * Protocol specification

Other specs and definitions

 * Blocks
 * Address
 * Transactions

Software

 * Bitcoin software on Sourceforge
 * Bitcoin-Qt client
 * BitcoinAverage API
 * BitcoinMonitor API

Sample files

 * Block Explorer: a Bitcoin archive
 * The "Genesis Block"; first Bitcoin block ever generated
 * Genesis block in some other formats including raw binary

Bitcoin sites

 * Coinbase: a Bitcoin market/online wallet
 * Try Bitcoin
 * The Bitcoin Database

Current and historical prices

 * Bitcoin live price graph
 * Chart of historical Bitcoin prices in terms of gold

News coverage

 * Government Ban On Bitcoin Would Fail Miserably (2013-01-28)
 * Bitcoin ATM (2013-02-23)
 * Bitcoin value reaches new high against US dollar (that was $32; as of late 2013 it's now over $600) (2013-02-28)
 * Hackers steal over $12,000 in bitcoins (2013-03-08)
 * Bitcoins Seized by DEA (2013-07-09)
 * Bitcoin's vast ovvervaluation seems to be caused by usually-illegal price fixing (2013-09-13)
 * Person gets windfall from Bitcoins he forgot he owned; bought for $24 and sold for around $1 million (2013-10-25)
 * A Bitcoin Exchange Holding $4.1 Million For 1,000 Customers Has Simply Vanished (2013-11-12)
 * Sir Richard Branson's Out of This World Plan for Bitcoin (Internet Archive copy) (2013-11-22)
 * James Howells searches for hard drive with £4m-worth of bitcoins stored (2013-11-28)
 * Chinese government says Bitcoin cannot be used as currency (2013-12-05)
 * Casascius, maker of shiny physical bitcoins, shut down by Treasury Department (2013-12-13)
 * IBM Files Patent to Track Value of Digital Currencies (2013-12-19)
 * Into the Bitcoin Mines (NY Times) (2013-12-21)
 * Bitcoin Miners Ditch Ghash.io Pool Over Fears of 51% Attack (2014-01-09)

Academic papers

 * Paper criticizing Bitcoin (and the concept of decentralized currencies)
 * Paper showing that selfish mining behavior could end up dominating Bitcoin

Commentary

 * My adventure in donating bitcoins to the Internet Archive
 * Open source governance in Bitcoin
 * Anecdote about the wrong way to promote Bitcoins
 * The Bitcoin Network is 0 FLOPS
 * How the Bitcoin protocol actually works
 * Bits of Bitcoin – What To Call Them?
 * Why I want Bitcoin to die in a fire
 * Bitcoin Is Evil
 * The Values of Money: Bitcoin, Money, and Datalove, Part One
 * Why Bitcoin is Here to Stay, Whether Governments Like It or Not.
 * Dreams reflected in Bitcoin
 * Could Bitcoin Ever Stabilize Enough To Replace State Currencies? (video)
 * Let's Talk Bitcoin podcast
 * On Bitcoin, Magical Thinking, and Hyper-Capitalist Political Ideology
 * On the Matter of Why Bitcoin Matters

Other links and references

 * Wikipedia article
 * Getting started with Bitcoin
 * Video explains Bitcoin
 * What nobody seems to understand about Bitcoin (Cracked video)
 * Bitcoin survival guide