It's not going to work, the dsi isn't CAPABLE of streaming videos, even if it was, they would be deathly slow and laggy. So you people obsessed with watching videos on your dsi can give up now, and go buy a computer, or something.
Yeah, I didn't try either, i'm not guilible. My dad works at spielo[a g-tech company], he works with technology, computors/lottery machines/gambling machines etc. and so I know a lot about computors too. I even asked him once and he said you definately can't watch videos on the dsi.
It doesnt mean it wont in the future. html5 is slowly inching its way into the scene as a newer Flash replacement, this could work eventually but its very doubtful unless Nintendo and Opera update the DSi browser to recognize html5, since it will be easier to implement than flash.