Distributed applications are not new. The first distributed applications were developed over 50 years ago with the arrival of computer networks, such as ARPANET
"Since then, developers have leveraged distributed systems to scale out applications and services, including large-scale simulations, web serving, and big data processing. In my own career, which started more than 20 years ago, I have worked on distributed systems in the context of the internet, peer-to-peer networks, big data, and now, machine learning.
However, until recently, distributed applications have been the exception, rather than the norm. Even today, undergraduate students at most schools do very few projects involving distributed applications, if any. However, that is changing quickly..."