The earliest notable altcoin, Namecoin, was based on the Bitcoin code and used the same proof-of-work algorithm - and like Bitcoin, Namecoin is limited to 21 million coins. Introduced in April 2011, Namecoin primarily diverged from Bitcoin by making user domains less visible, allowing users to register and mine using their own .bit domains, which was intended to increase anonymity and censorship resistance.
According to BitPay, a Bitcoin Payment Service Provider, as of November 2013 there are over 14,000 merchants currently accepting bitcoins. Two years ago this number stood at few hundred. The number of transactions facilitated by Bitpay increased tenfold in 2014 and crossed the 50,000 mark in November. The payment processor said that 6,296 bitcoin transactions occurred on Black Friday last year, up from only 99 transactions the year prior.
Altcoins began life as little more than bitcoin copies attempting to mimic bitcoin’s successful run, but they quickly became much more than their name suggests. At the time of writing (February 2018), there are more than 1,500 altcoins available for use. While many are still struggling to break the mold set by bitcoin, some are doing truly amazing things with the technology.
Bitcoins are mined with powerful computer hardware and software. A maximum of 21 million Bitcoin will be available, after which no further bitcoins will be produced. The algorithm which governs the production of Bitcoin limits the quantity that will be produced, and the rate at which they will be produced. It is a finite commodity – there is a fixed amount, and that ensures that greater demand will always prop up the price. In this way, it is similar to other finite commodities such as crude oil, silver, or gold.