There is one, at least, participant in this forum that is concerned with hoarding of BC, please allow me to explain why this is not an issue, not because it will not have negative effects if it does, but more likely it will not occur.
What we must keep in mind is there is yet a coherent value model for BC, when I first got here many were assuming cost equals value, which simply is not true, I have said it time and time again, value is not based on cost, but rather on the demand for a commodity, right now there is little to no demand for BC. There may be in the future, but that is speculative and is related to a few factors which relate to the general utility of BC as a medium of exchange.
BC as a commodity has no value without a commodity that may be exchanged for BC, there is no other use for BC than a medium of exchange. Commodities with an inherent value have an ordinal utility within themselves, that is, they have an industrial, commercial or consumer use, you cannot compare BC to land capital, other capital or commercial goods because of this fact.
The other way a commodity can retain value is through government fiat, that is legal tender laws, basically by the forced use of particular monies, these monies retain their utility because other options are illegal and the basic coercive threat maintains their usage.
BC does not fall within either group of commodity, its value is determined by its ability to out-compete its substitutes, it must therefore be used as a medium of exchange for goods in order to have a value.
Hoarding is deleterious to the ability of BC to out-compete its substitutes, as it will raise relative prices in BC and the exchange rate to other currencies, while other currencies will not be incurring the same price explosion. As opposed to legal tenders, there being no government fiat coercing utility people will abandon BC if the substitutes are more beneficial. In the end, the hoarder who keeps BC as an investment in the future value of BC gambles with his money. If he does not use them, sell them or lend them to someone who will use them at interest and just pulls them from the market the lacking availability of BC will diminish the value as there is no other use than as a medium of exchange. The increase in price, $ purchasing value, coupled with a stable commodity price structure, of BC will be an indicator to the wily entrepreneur that something is wrong, and these people will stop using BC first. This will start a chain reaction that will give the illusion of the desired result in the "stock" market numbers, the same boom in $ value of BC without corresponding increase in production available to be traded in BC is a business cycle bubble. If the hoarder at this point does not cash out immediately, which is relatively difficult, he will be holding BC in the bust, and therefore lose out.
This is also leaving out the whole world of whether it is more profitable to a "hoarder" to lend his BC at interest to producers, invest in productive business himself as a shareholder or to use them in the market for consumer goods than it is to just sit on anonymous internet blips that have no value inherent to themselves...
Lending at interest
I know there are people who like to boo and hiss usury, but it is a natural market phenomenon based on production, charging above the natural interest rate is a side effect of time preference, get over the communist propaganda please.
If I were to be a hoarder, let us say I have control of 60% of all BC, and have no intention to use them, why would I not lend them at interest? If there is a market demand for BC, and I have BC, it makes no sense that I would not take advantage of the market demand, it is like saying that a producer has no impetus to sell his products, when he can just sit on them indefinitely. Why does the stereo manufacturer sell stereos? If he produces $1000 stereos, by the hoarding logic, holding them instead of selling them will make him wealthier and increase the value of his stereos this is not the case for stereos, nor BC.
No, lending is more practical than holding BC in the hopes for increased value. Predatory interest rates will be curtailed by the free nature of the market, as anyone can lend BC so long as they have a surplus of BC beyond their usage, there will be large amounts of competition in this field, which will lower lending interest rates.
Investment
If I am holding 60% of all BC, why does in not make sense to invest in businesses? If I believe that there is a good business, even if they are not looking for shareholders, why would I not want to attempt to purchase a minority share of that business and receive a dividend based on their profits? In the long run, I would benefit more buy purchasing 1% of a business than not at all, not only because of the real gains in BC over time, but because the value of BC will increase when there is more products available in BC, there will be more demand for the very bitcoins in my coffers, a net gain at the natural interest rate.
Spending
Is the argument that I will sit upon my digital throne, resting atop my digital blips? Would I be enjoying some superiority because I am wealthier in BC than others? If this image is just silly to you, well you are correct, if you still at this point believe hoarding is a good idea, this is exactly what you are claiming. If I have 60% of all BC, what is the point, how do I benefit from my majority stock of BC if I do not acquire consumer goods with them, or sell them to people who will?
The hoarding mentality can only be directed at BC that is not being used, which at this stage of BC can be all of us who hold any, as there is not very much that can be bought through BC. However as the BC marketplace fills with goods and services, we will see a decrease in nominal prices and an increase in the BC/$ ratio. This will only occur if people are spending BC, if they are holding them businesses will not accept BC when they can accept any other media of exchange.
If BC's value is based on exchanging them for goods, how exactly is the hoarder protecting his BC's value if he does not allow them to be exchanged? Any way you slice it, exchanging BC for goods and services is how BC has value, hoarding them negates this and therefore negates the purpose of hoarding...
I am sorry to say to the developers of BC that this may not be the finished product, they may go through many trials before a viable economy is derived from a counter-economic currency, we should persevere to make this one work, but keep in mind it is a learning experience and it may fail...