Viddix is a freakily great site that lets you put documents, web content, powerpoints, photos, surveys (and more) next to video content. You can even trigger the accompanying documents to appear at the correct place within the video. Have a look at this example:
Created by a Dutch group, Viddix has free and business accounts. Viddix could be extremely useful for conference presentations, whether they be virtual or face-to-face. And as you can see, Viddix presentations can be embedded quickly and easily as there is only one embed code.