First, **there will be no "killer app" for blockchain technology**....Perhaps the best analogy to this line of reasoning is to ask the following rhetorical question: what is the killer app of "open source"? Open source has clearly been a very good thing for society, and it is being used for millions of software packages around the world, but nevertheless it is still hard to answer the question. And the reason is the same: there is no killer app, and the list of applications has a very very long tail - basically, just about every kind of software imaginable, with particular emphasis on lower-level libraries that end up reused by millions of projects many times over and critical cryptographic security libraries.