Video - Bitcoin Q an A What is the role of nodes?
The role that full nodes play in security of the network. People focus a lot on mining, which has a fundamental role in the network but is not necessarily the most interesting feature of the constellation of technologies involved. The Border Gateway Protocol (BGP) is the most essential protocol underlying the world's routing system, and you use it every single day without knowing it, just as you are oblivious to the vast filtration system allowing you to drink clean water from a fountain.
A node is a computer that is participating the global peer-to-peer Bitcoin network. They propagate transactions and blocks everywhere. Full nodes act independently as authoritative verifiers. Onion routing. Double-spending protection. Levels of isolation for untrustworthy nodes. Why would you run one? To be in control of your money - your keys, your money. You don't trust anyone else to tell you what the truth is, you cross-check every claim yourself. Be part of the revolution in money.