Beet.TV interviewed Blip.TV's Dina Kaplan, and highlighted her comments about video advertising standardization -- or rather, the need for some. Her point is that advertisers at this point have no real certainty of what their creatives will look like as they fan out across a multitude of websites.
You can see her conversation at: http://www.beet.tv/2008/02/standardization.html [1].
The question is, is she right? She certainly makes a great point, but breaking free from old boxes is supposedly one of the web's greatest benefits. If you want to film an ad that runs 1:48, you can -- and in whatever aspect ratio best fits your purpose.
In other words, should pragmatic logistics trump creative [2] ideals?