The internal measures, unfortunately, are very easy to game. Take, for instance, an option that is now being considered among academics for regular currencies: NGDP targetting. It'd be very easy to check the NGDP of a cryptocurrency: It's really just trade volume. So it'd not be difficult to attach a coin's supply increase to the volume. We could pick a currency's codebase and make a competitor that did such targeting withing the day. The problem is that it would not work.
NGDP for a real country is fairly hard to game. It's not as if I can suddenly create real economic activity without major costs to myself, at the very least in taxes and fees. The money is also spread enough that such effort would not really match rewards, even in an NGDP targetting regime. In a cryptocurrency though, it's another matter. Transaction costs are tiny for large transfers, and someone with a large balance would be able to create large volume for pennies. Those that would have an easier time doing this are those with a lot of coin, which are exactly the people that would have a lot more to gain from currency manipulation.
I lack any mathematical proof that a stabilization system that is based on what a user cares about, expected value of the coin in a few months/years, is not possible. However I'd be very surprised if there was a solution that worked in the case that a few actors control a significant percentage of the coin's supply, and as it is, this is a characteristic shared by every major cryptocurrencies today.
What makes things worse is that many cryptocurrency proponents would consider any of this stabilization mechanisms to be undesirable anyway. So even if we found a way, would the many people that believe that devaluation hurts savers be on board? A currency that did manage do behave a lot more like a traditional currency would probably not be what those people want, regardless of what the state of the art in economics believes.
So we are back to Betteridge's law of headlines: Any headline which ends in a question can be answered with the word no.
[0]: http://computationallyendowed.com/blog/2013/11/27/bitcoin-de...
NGDP for a country is merely a statistic compiled by the local government's statistical agency. Like other economic metrics it can be gamed (see Argentine inflation stats), or more commonly, "lite gaming" where people pick a definition of the statistic that is a good fit for their political goals.
Two examples spring to mind. The UK recently got hit with a large bill by the EU. The reason is that a new method of calculating GDP was introduced that tried to incorporate economic activity from the black market (drugs, prostitution etc). This raised the UK's overall GDP by enough to also raise its expected contribution to the EU budget. Is the new GDP statistic more accurate than the previous one? That's hard to say, almost by definition because the activity they're trying to include isn't being reported to any government. It boils down to a guessing game.
For another example, look at the the way house prices are incorporated (or not) into inflation calculations. Turns out countries around the world don't agree on the best way to do this, and use varying methods. Some ignoring housing entirely, others ignore house prices and try to guesstimate what the rent for a property would be (very hard if there are not many renters in the area), etc. It's all rather debatable - and debated.
> This makes trying to stabilize the price to some set of goods very difficult, because no matter what you pick, you'll have to cut supply somehow, and that just won't work without something akin to a central bank.
I'm interested to know which central bank you are thinking of that has recently cut the money supply (btw "money supply" in economics normally means the amount of all money in circulation, not the growth in it). All central banks I know of only ever create more money, they hardly ever (never?) bring down the monetary base long term.
Regardless, you're correct that many cryptocurrency proponents (like me) don't want to see some kind of Soviet style planning committee in charge of the money supply. Partly because there's little evidence it would work. The really sharp changes in Bitcoin's value occur due to press cycles, government actions and press cycles triggered by government actions. For example the huge spike last year was triggered by a combination of the first Silk Road shutdown, a favourable US Senate hearing, and huge activity in China being firstly pumped by that countries capital controls and then suddenly cut off due to enforcement of the same.
But eventually, it seems like these events will stop happening. Governments will have mostly taken an enforceable position on Bitcoin one way or another, so that source of unpredictability will go away. The press will lose interest. Everyone who cares will have heard about it and made a decision. Bitcoin will become boring. At that point I'd hope (and expect!) that it'd be rather stable indeed, or at least the value would slowly fall due to the inflationary pressure. During quiet periods when nobody is really paying attention to Bitcoin its value fluctuates much less.
Monetary policy is a mechanism to control long-term value of currency, for example to limit inflation or maintain a certain exchange rate with a foreign trade partner. It's not intended to (nor is it able to) damp out short-term fluctuations in foreign exchange markets.
[0]: http://en.wikipedia.org/wiki/Impossible_trinity
[1]: http://www.nytimes.com/2010/07/11/business/economy/11view.ht...
The monetary policy follows the block reward (currently 25 BTC).
Of course with this monetary policy and free movement of capital, it is impossible to have a fixed exchange rate, but it does in fact have two out of the three.
It isn't a currency, it's a transport mechanism for currency.
If you approach it from that perspective, the current value of bitcoin is irrelevant. Sure, if a business wants to be paid in btc, then they'll have to dynamically price based on the current value of btc and then immediately convert to fiat...
That also makes it a pretty awesome way to do cross currency conversion without much overhead. Want to pay euros for a product priced in US dollars - (somewhat) easily done with btc... and without (some) of the overhead/fees involved in traditional banking/credit cards.
Now, if you're looking at it as an investment - well, enjoy the ride... I could have bought 15 btc in Feb 2013 but instead I bought a bitcoin asic miner - that was promised to be delivered by May... and it showed up in October. If I had bought the btc, it and sold it in Nov/Dec 2013... well, I would have been much happier than I was simply breaking even on the miner. (120x happier, in fact) :)
