"A fork is a situation in which a blockchain splits into two separate chains temporarily or permanently." -Wikipedia.
Check out these links on hard and soft forks as well as some information on technical issues like replay attacks.
- "Can Bitcoin Hard Fork?" - Investopedia.
- "A Painful Lesson For The Ethereum Community" - Forbes.
- "Official NXT Decision: No Blockchain Rollback" - Cryptocoin News.
- "A Short Guide to Bitcoin Forks" - CoinDesk.
Statistics from www.coinmarketcap.com:
Jan 19 2018 00:02:00 UTC
$563,281,000,000 USD: Total Market Capitalization
$49,456,100,000 USD: 24-Hour Volume
34.11%: Bitcoin Dominance