Using a PC with Windows & it seems I only have that problem with Yahoo7! Australia website.
All other Yahoo websites (USA, Europe, etc) are working fine.
When opening a Yahoo!7 website with several videos,
they sometimes start all at the same time &
I have to pause some of them,
so I can view one video without being disturbed by the audio of the others &
maximising a video shows only a black screen,
but you can hear the audio.

Checked an article on huffingtonpost.
To be specific: http://www.huffingtonpost.com/entry/salem-witch-hangings_56988f87e4b0ce4964240f0e?
While you view a video you can scroll down the page & the video minimizes visible on the right.
So you can watch the video at the same time,
while exploring the rest of the webpage.
I've never seen this feature elsewhere & thought it was pretty awesome & time saving.