I already tried the embeded video from youtube, that is the way i was placing it in the product description like you said - from source view and copy/pasting it in there and before i save it, when i return to normal view i see a iframe with a start button for the youtube video, although i dont see the background image of the video like i normaly should. When i save it after i placed it there just like you said, when i go to the product page of that particular product, where i placed the embeded video it doesn't show or render if you will. And that is why I'm wondering if it has to do with some sort of settings, either on my server or the nopcommerce installation it self...
are you sure it is not some kind of caching issue? Have you tried changing something else in the description of any particular product just to see if the changes will appear on the public site?
If it is not cache, then the video should be there but something might be hiding it. Are there any errors in your browser's console? Can you please provide a link to a page where you have included a youtube video so we can see if we can find what the problem is.
Looking forward to your answer!