Minimum number of all users, or minimum number of users in the top brackets? Because we know we've had over 100,000 bitcoin users since Summer of 2011.
Sorry to bring up this question repeatedly:
What do we know concerning number of users (now or at any time in history)?
- Blockchain activity?
- Downloads of Bitcoin client and wallet software
- Forum accounts
- Number of users in exchanges
- Number of users in other services
- Other ways of receiving this info
We knew there were about 65,000 users on MtGox as far back as Summer of 2011. MtGox also claimed to have 25,000 new applications every month this past winter, and 50,000 new applications in March and April. Blockchain.info also recently mentioned reaching 300,000 wallets. The defunct instawaller boasted about having over 1 mil wallets, though many of those may have been throwaways. We also have a list of Bitcoin-QT downloads that shows that this wallet has been downloaded 2.9mil times already (
http://sourceforge.net/projects/bitcoin/files/stats/map?dates=2009-01-01+to+2013-04-30). Even if some of those were downloaded and abandoned, there are tons of users who used other services, like blockchain, electrum, multibit, or android wallets instead. So I would estimate the current number of bitcoin users at 1,500,000 at the bare minimum, and more likely closer to 2.9 to 3.25 mil.