The evolution of technology has fundamentally changed people's lives. Throughout human history, machines have replaced humans for performing various tasks. For example, in agriculture, farming vehicles made farming work less labor-intensive and greatly increased productivity. In the US, as of 2008, less than 2 % of the population directly work in agriculture. They not only supply the food needed for the other 98% of the population, but also make the US the biggest agricultural products exporter. Examples in other areas include programmable telephone switchboards replacing telephone operators, and automatic elevators replacing elevator operators.

This trend of machines replacing humans sped up in the last several decades, largely due to the invention of computers. So far, there have been three computer-led revolutions in technology. Each of these revolutions fundamentally affected existing business models and inspired new ways of doing business. We are now at the dawn of the fourth phase: a blockchain technology-led revolution. The following are the phases:

• Invention of mainframe and PC: Computers replaced humans for performing repetitive computations faster and better. Applications of computers driving automation are numerous and everywhere.
• Internet: The internet refers to a globally interconnected network of computers. The arrival of the internet fundamentally changed the way services are delivered. For example, in the 90s, renting a video cassette or CD/DVD at a local rental store was a popular family entertainment activity on the weekends. Blockbuster was a household name offering rental services, and its business model worked well. In 2004, Blockbuster employed 84,300 people worldwide and had 9,094 stores in total. With the internet, new companies such as Netflix emerged and disrupted the reign of companies such as Blockbuster. Families no longer need to make a trip to a physical rental store to pick up a CD/DVD. Instead, they can downloaded a virtual copy of a movie from the internet. In 2010, Blockbuster filed for bankruptcy. Today, Netflix is a 145B company. The same story has repeated itself many times in other areas.
• Social media sites: Social media sites such as Facebook, Twitter, or YouTube not only changed existing business models, they changed the way people obtain news and how news is distributed. Papers and radio/TV-based news distribution are no longer the only channels for news dissemination. Many news publishers were forced to shut down due to the loss of subscribers. On the other hand, freelance news reporters started emerging via YouTube and so on. Social media sites have also fundamentally impacted governments as news censorship became more difficult.

Phase 4—blockchain technology: Even with social media sites, censorship—although more difficult—is still possible since information is hosted and processed at a centralized server, so censorship can be implemented at that centralized server. With a blockchain network, censorship is not practical thanks to the decentralized design of blockchain technology. The only way is to shut down all the nodes of the network within a country. The biggest impact of blockchain on existing business models comes from the fact that this technology will make intermediary services obsolete. It will particularly affect the financial industry, where most financial services are essentially intermediary. This technology is about to bring changes not just to the financial industry, but to virtually every other industry.

Next, we cite a few examples of potential blockchain technology applications. We use the word potential, since the technology is still evolving and its current form has many limitations. There is no guarantee that these use cases can be implemented. It will take a while before many of these use cases become a reality, and some may never come to fruition. Regardless of whether a use case can be implemented or not, we focus our discussions on business problems and on ideas of how business pain points can potentially be addressed via this technology. As the technology advances, for example with improvements in performance, some use cases will become a reality. We first talk about use cases in the financial industry.