One thing that has been interesting to watch is how the VP9 codec has come along. When I posted the first beta, VP9 was experimental, had hardly any application support, and was incredibly slow to encode. Today you can play VP9 in Firefox, Chrome, VLC, and other standards-compliant software. And VP9 encoding…well, let's just say it's a lot faster than it used to be, thanks to multithreading and countless other optimizations.
