Just by clicking your link and then going to share it from the YouTube app share button, I get this:
That SI code contains something about how the link has been shared, likely telling YouTube that my specific account has been used to share it to whoever clicks it. It probably has info about how I found it as well, such as direct link, yt suggestions, yt homepage, yt Playlist, etc. Now we're related. Now my analytics will be buddied to yours. Now it that it knows we both like 80s pop music, it'll tell you to watch some other things I find fascinating. (at least, if the link is opened by someone logged into their yt account)