Netflix delivers all video streaming content via FreeBSD which makes up 37% of all internet traffic. https://openconnect.itp.netflix.com/software/ They also contribute to FreeBSD core. It is not just an "appliance" as some people seem to want to point to.

https://www.youtube.com/watch?v=4sZZN8Szh14

https://www.youtube.com/watch?v=KP_bKvXkoC4

https://www.youtube.com/watch?v=FL5U4wr86L4

In addition, a guy I met, who worked at Yahoo, told me about 25% of Yahoo still runs FreeBSD as of two years ago.