Bitcoin has nearly 100,000
Indeed, it is often reported that Bitcoin has somewhere around 9,000 to 10,000 full nodes validating its blockchain (Hard Fork has done this, too!).
According to prominent Bitcoin Core developer Luke Dashjr, that number is closer to 100,000 – and he says it’s because other node monitoring services typically include only one type of node (“listening nodes”).
Whether nodes are “listening” isn’t all that important
The security of the Bitcoin network can be gauged by the number of nodes that keep a complete copy of its blockchain.
These are referred to as “fully-validating nodes,” or “full nodes” for short. Bitcoin miners broadcast messages (transactions) across the network for validation using these full nodes.
A higher number of nodes increases the overall security of Bitcoin by making double-spending more difficult for malicious miners.
Dashjr previously told Hard Fork that popular sites like Coindance only show Bitcoin‘s “listening nodes,” but whether a node is “listening” is a mostly-irrelevant technical detail.
Listening nodes are essentially the same as full nodes, but publicly visible.