The 21 Full Nodes IndexBitcoin full nodes help preserve the health of the Bitcoin network by validating blocks and transactions, and then serving those validated transactions to lightweight clients and other full nodes. This helps blocks and transactions propagate quickly and navigate their way past obstacles in the network, ensuring that everyone has full access to the blockchain. As lightweight clients currently make up a significant and growing part of the network, it’s essential that we help them maintain their high level of security — which means maintaining a critical mass of full nodes. We’re contributing towards that in three ways — better metrics, greater ease of use, and mining incentives.
https://medium.com/@21dotco/the-21-full-nodes-index-f73a628b4762
