Bitcoin and Ethereum's leading forks aren't very big
There are two "leading" forks of the two biggest blockchains, Bitcoin Cash and Ethereum Classic — neither of them are doing great, compared to their parent chain.
Why it matters: Because blockchains run on open-source software, they can always be forked — the term for when someone makes a change that's not approved by the developers in charge of a codebase. This provides a check on the developers who maintain that codebase, making sure they don't veer wildly away from what their users want.
Ethereum and Bitcoin have both experienced headline-grabbing forks.
- Bitcoin was forked at the end of the so-called "Block Size War," which yielded Bitcoin Cash, from Bitcoin proper, in 2017. Everyone who had bitcoin when the chain split suddenly also had Bitcoin Cash.
- Ethereum Classic was created after Ethereum hard forked in 2016 following the theft of funds held by a project called "The DAO." A small subset of miners kept running the original chain and it persists to this day.