The core fundamental aspect of Bitcoin is its censorship-resistant nature; this is only possible because the network is meaningfully decentralized.
Decentralization is achieved by bitcoiners worldwide running nodes (a computer connected to the bitcoin network, e.g. Bitcoin Core).
These nodes maintain the network rules, known as consensus, and ensure all transactions and blocks are valid by keeping a copy of the entire history of the blockchain.
Aside from supporting the network, running a node helps improve your privacy and allows you to validate your transactions without requiring a 3rd party. If you are not running a full node, you cannot use the bitcoin network in a trustless way.
It is hard to know the exact number of nodes connected to the bitcoin network. However, Luke Dashjr estimates the number to be somewhere around 80,000.
In this interview, I talk to Shinobi, the host of Block Digest. We discuss what a node is, why running a node is crucial for the network, which hardware & software to use, and the impact on privacy.