In order to provide their entertainment services to thousands of customers around the world, Netflix has set up its own content distribution network (CDN). It is called Open Connect and is made up of custom hardware and software based on FreeBSD.
The simplified BSD license of this OS offers great freedom to Netflix developers, who are not required to publish the code they have modified from the original system to.
The main reason why they use this OS is its great performance. After customizing it according to their needs, they managed to reach rates of 90 Gb/s in encrypted connections, and most striking: consuming only 55% of the CPU in a system with 16 cores to 2, 6 GHz.