In the early 2000s, one of the most popular pieces of software in the world was a free peer-to-peer file-sharing network called Kazaa. It was launched by two Scandinavian entrepreneurs, Niklas Zennström and Janus Friis, with the simple idea that internet users should be able to share anything with anyone in the world.
After being knee-capped by lawsuits from the music industry, Niklas and Janus applied peer-to-peer technology to a new business: Skype, a service that allowed anyone with an internet connection and a microphone to talk to anyone else in the world… for free. At its peak, Skype connected hundreds of millions of global users, and in 2011, it was purchased by Microsoft for $8.5 billion.