Here is a test site. I have disabled scripting to simplify things. For embeddings, I have everything enabled except for Collapse Blocked Objects.
Here is a screenshot of what I see:

If I click on the placeholder icon on the webpage, it does NOT allow the video to play. Based on the confirmation dialog I receive from the placeholder icon, I think the placeholder icon is allowing the 3rd BO entry in the menu (but I'm not sure of this). What exactly is the difference between the 3rd BO entry and the 4th BO entry (what are the different icons telling me exactly)? Obviously the 4th entry is a video icon but the 3rd icon is one I usually see for scripting and I have scripting disabled so what is that icon communicating (what does it do if I allow it)? If I allow just the 3rd BO entry the video does not play, so what did it allow?
1st entry: I don't know what this does
2nd entry: this allows ?what? if it comes from googlevideo.com?
3rd entry: this allows ?what? if it comes from googlevideo.com (source?) and youtube.com is the site that's displaying it?
4th entry: this allows video to play if it comes from googlevideo.com (source?) and youtube.com is the site that's playing it?
5th entry: this allows video to play as long as googlevideo.com is the source?
Based on my reading of the other thread, is it correct that the first domain listed in an entry is the source of the object and the second domain listed (the one in parenthesis) is the domain that is allowed to play the object if it comes from that respective source?
There's another screenshot I took from the same webpage that adds a whole section involving apis.google.com as an iFRAME. Maybe we can explore this menu once I fully understand this current menu I'm discussing? If so I'll post the screenshot a little later.
Thanks a bunch guys.