And what is the important of running a node?
Bitcoin is essentially a piece of software.
Nodes are computers that run this software.
Without nodes, there can be no Bitcoin.
Nodes are responsible for:
1. transmitting the blockchain to other nodes, maintaining snapshots of the blockchain.
2. validating transactions, making sure they follow the same set of rules.
Running your own node helps because:
1. you can keep a copy of the blockchain for yourself. This is brilliant, because it gives you the opportunity to "know" the truth.
2. you can validate transactions & blocks without trusting the rules that other nodes use.
3. you can be private, not asking anyone about anything.
4. you help the network. One more node is always better.