I really do not know what kind of metrics are available for measuring the size of the Bitcoin community, but I am interested in any metrics indicating how many users of Bitcoins that there are. Some example metrics could be:
- Number of registered users on forums
- Number of wallets
- Number of wallets with bitcoins in them
- Number of non-mining clients running
- Number of installations of default client
It would be excellent to see these numbers in relation to some numbers, like the size of the BitTorrent community (or maybe the old Napster community) or whatever, to get a better understanding of the number, but this is not necessary.