I've heard estimations there are anywhere from 1.5 to 2.5 million Bitcoin users currently, which is obviously peanuts compared to the potential user base out there.
But currently, how many of those would we figure actually research the fundamentals of bitcoin and see it having a very large role in finance vs. those who are simply interested in the market side of bitcoin to gain fiat currency?
I would categorize bitcoin users into three categories:
1) Speculating investors. They provide the initial value to bitcoin, based on belief of the future utility of the digital currency.
2) Bitcoin consumers, people that use bitcoin to actually buy products and services
3) Businesses that accept bitcoin as payment.
Businesses that accept bitcoin cannot be expected to hold bitcoin for more than a few minutes, because presently, it would be fiscally irresponsible for a business to hold a currently volatile speculative investment for any significant period of time. This also applies to non-hobbyist miners.
Investors and investment are not going to increase until there is more commerce using bitcoin, that is, until more consumers are using it to buy goods and services, which creates demand for bitcoin that is not purchased as a speculative investment.
Until the ratio of bitcoin consumers to investors increases, volatility will plague bitcoin. The best way forward is to encourage the use of bitcoin in commerce, find more attractive ways to buy things and services with bitcoin over government currency.
I think the biggest battle will be with the credit/debit card system, since they have hidden their fees from consumers by making retailers pay for it, which is indirectly paid for by non-card using consumers.