These are the YouTube Specifications on their web site:

Resolution: 1280 x 720 px or 640 x 480 px
Bit Rate Optimize for resolution, aspect Ratio, frame rate (not bit rate)
Frame Rate: TBD
Codec:  H.264, MPEG-2 or MPEG 4

Audio: MP3 or AAC
Sample Rate: 44.1 kHz
Channel: 2 (Stereo)

Length: 10 min (There is a exception to this, but if you create a video longer it better be a major motion picture)
File size: 100 meg max (So far)

This seems to be the important technical aspects I have briefly found. Please add to this list if you think it is important.

Perhaps we should set up a specific “technical specs” forum for this.  Although it is about the mechanics of social marketing/media.

Yes, a media technical forum would be a good place for this type of information. It would also be good to continue the conversation on how various contributors of media can help each other.