Speculation is a part of the free market :)

and what's wrong with that? bitcoin is currently more like a stock as the market is waaaaaay too small, and thus you cannot expect stability from it. it will soar, and it will crash, many many more times. but more importantly, it will survive all that and grow steadily in the long term. long term investors are not affected by these bubbles anyway.

If the rising dollar volume crossing the blockchain outpaces the rising exchange rate, then it is sustainable. The blockchain output cannot be estimated with certainty though so that will always be a best guesstimate.

But certainly the bulk of the value remains from speculative interest rather than organic demand for the coins for use in commerce.

And that's exactly what I want, since I can buy low again. :-P