LarryHN, you are incorrect.
dwd40 is talking about "Shared Photo Streams" also called "iCloud Photo Sharing" - which suports video.
This is the doc: http://support.apple.com/kb/TS4379
My Photo Stream, which you are confused with does not support video.
The doc linked above says that the new Shared Photo Streams are only supported on the PC, iOS and Apple TV:
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What software versions do I need to be able view and share videos, and contribute to other people's shared streams?
- iPhone, iPad, or iPod touch with iOS 7.0 or later
- PC with Windows 7 or later and the iCloud Control Panel 3.0 or later
- AppleTV (second generation) with Apple TV Software Update 6.0 or later
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No support on Mac yet. There is likely an updated version of iPhoto coming soon that will bring the functionality to the Mac.