In a Ponzi scheme using bitcoins, the Bitcoin Savings and Trust promised investors up to 7% weekly interest, and raised at least 700,000 bitcoins from 2011 to 2012. In July 2013, the U.S. Securities and Exchange Commission charged the company and its founder in 2013 "with defrauding investors in a Ponzi scheme involving bitcoin". In September 2014 the judge fined Bitcoin Savings & Trust and its owner $40 million.
Shipping containers make for a quick way to set up an industrial bitcoin mining operation, but the servers inside produce so much heat that large fans are needed to move incredible volumes of air at high velocity in order to keep them overheating. At top, workers have attached ducts to the hot exhaust, carrying it over to melt the frozen worksite and warm their lounge area. | Patrick Cavan Brown for Politico Magazine
Computing power is often bundled together or "pooled" to reduce variance in miner income. Individual mining rigs often have to wait for long periods to confirm a block of transactions and receive payment. In a pool, all participating miners get paid every time a participating server solves a block. This payment depends on the amount of work an individual miner contributed to help find that block.
When you pay someone in bitcoin, you set in motion a process of escalating, energy-intensive complexity. Your payment is basically an electronic message, which contains the complete lineage of your bitcoin, along with data about who you’re sending it to (and, if you choose, a small processing fee). That message gets converted by encryption software into a long string of letters and numbers, which is then broadcast to every miner on the bitcoin network (there are tens of thousands of them, all over the world). Each miner then gathers your encrypted payment message, along with any other payment messages on the network at the time (usually in batches of around 2,000), into what’s called a block. The miner then uses special software to authenticate each payment in the block—verifying, for example, that you owned the bitcoin you’re sending, and that you haven’t already sent that same bitcoin to someone else.
In March 2013 the blockchain temporarily split into two independent chains with different rules. The two blockchains operated simultaneously for six hours, each with its own version of the transaction history. Normal operation was restored when the majority of the network downgraded to version 0.7 of the bitcoin software. The Mt. Gox exchange briefly halted bitcoin deposits and the price dropped by 23% to $37 before recovering to previous level of approximately $48 in the following hours. The US Financial Crimes Enforcement Network (FinCEN) established regulatory guidelines for "decentralized virtual currencies" such as bitcoin, classifying American bitcoin miners who sell their generated bitcoins as Money Service Businesses (MSBs), that are subject to registration or other legal obligations. In April, exchanges BitInstant and Mt. Gox experienced processing delays due to insufficient capacity resulting in the bitcoin price dropping from $266 to $76 before returning to $160 within six hours. The bitcoin price rose to $259 on 10 April, but then crashed by 83% to $45 over the next three days. On 15 May 2013, US authorities seized accounts associated with Mt. Gox after discovering it had not registered as a money transmitter with FinCEN in the US. On 23 June 2013, the US Drug Enforcement Administration (DEA) listed 11.02 bitcoins as a seized asset in a United States Department of Justice seizure notice pursuant to 21 U.S.C. § 881. This marked the first time a government agency had seized bitcoin. The FBI seized about 26,000 bitcoins in October 2013 from the dark web website Silk Road during the arrest of Ross William Ulbricht. Bitcoin's price rose to $755 on 19 November and crashed by 50% to $378 the same day. On 30 November 2013 the price reached $1,163 before starting a long-term crash, declining by 87% to $152 in January 2015. On 5 December 2013, the People's Bank of China prohibited Chinese financial institutions from using bitcoins. After the announcement, the value of bitcoins dropped, and Baidu no longer accepted bitcoins for certain services. Buying real-world goods with any virtual currency had been illegal in China since at least 2009.