Abstract
Most people consider financial bubbles as the result of speculations and manipulations, and that less of them will make a market economy more efficient. While speculative bubbles no doubt increase the risks and uncertainties of investors, there are many episodes in human civilization where financial bubbles are commensurate with real positive contribution to real development of an economy. This paper analyzes this issue from theoretical perspectives and in the context of recent new financial instruments created from the technology of blockchain.