Congratulations OP ! You are the real PRO analyst. I have never seen such deep analysis and understanding of Youtube Algo coming from a non-coder guy.
Also For People Wondering Which type and Why External Views work ?
Answer:-
Its not new that Youtube Gives much credit to external HR views, i see it doing from 2013 as always and there is a solid reason behind it.
First of all It Only Works For External video as Embeded. So linked keywords etc won't work much as the embed ones do.
Why Hyperlinks do not work much ?
Answer:
When you click on hyperlink it takes you to youtube website or app. So basically that means user wanted to go to youtube and spend some time there.
Why Embed ones work much more ?
Answer:
Whenever you play youtube video from embedded source, user does not leave the main website and plays in an iframe player. That means thee user does not want to go to youtube but even though it is watching the youtube on other social media and it is a direct signal that the content is very interesting to users and because of that content the user is giving more time on youtube than wanted on other social media. So youtube reward those videos and boost it to maintain trends according to other social media also, so they can provide all users a relative viral content across multi-social media channels.
Embeded videos from custom domains do not work, it only works for main social media channels like reditt,fb,twitter etc.
This works for all old and new videos.
Source: Self Testing and Experience.
i hope this will help someone to clear the confusion and get more understanding of Algo a bit.
