It cannot be denied that a large portion of videos stored on the internet can be found on YouTube. Isn’t it frustrating then that when you navigate to the web interface on YouTube and look for the Picture in Picture button, there isn’t one there?
Well with macOS Sierra, it IS possible to play this video and have it displayed in a corner while you work on other things (if that’s your bag - personally it’s not mine!)
If you control or right-click the video, you’ll see a contextual menu. Sadly, the first time you do this, there is no option for Picture In Picture.
Don’t give up though. Do it a second time and you’ll see a nice new option appear. Select Enter Picture In Picture and you’re off to the races
Quick tip, but surprising to many people