How big is the Bitcoin network in terms of total number of computers (peers, clients) that are connected together? Are there any network statistics or historical size data available?
My current real-time estimate using https://github.com/ayeowch/bitnodes is 8000 to 10000 nodes that are reachable at any one time with churn rate of 300 to 500 nodes every 5 minutes. The churn could be due to several factors, e.g.
- Node went offline
- Node reached max. allowed connections
- Time of day, e.g. more nodes are online during US working hours
- Network errors
There is no definitive answer because the network changes as nodes connect and disconnect. Blockchain.info maintains some statistics that might help you. Try going here to get a list of nodes that have connected recently. This still won't tell you the total number of nodes in the network, but it gives you an idea. They also maintain a list of nodes that have been contacted over the past 48 hours.