I was part of Pluto's launch team. We used to literally just be 95% YouTube embeds that were forced into a live-like experience client-side. Getting simple YouTube or even HTML5 video API calls to work reliably in 2013 was quite a feat. Loads of people still had Flash, mobile browsers were a crapshoot, and I caused many many thousands of early Amazon Fire TV hard restarts due to crashing their (kernel?) video decoder somehow.

Fun times.