Hi,
in Wikipedia, I found the following:
Each miner node works on finding a difficult proof-of-work for its block.
When a node finds a proof-of-work, it broadcasts the block to all nodes.
Nodes accept the block only if all transactions in it are valid and not already spent.
So far, so good. But how does a pool decide to which nodes it will broadcast a block? By the best connection it has to the node, randomly, latency?