Talking heads encourage wandering eyes...
Web design guru Jakob Nielsen says :
"Eyetracking data show that users are easily distracted when watching video on websites, especially when the video shows a talking head and is optimized for broadcast rather than online viewing."
http://www.useit.com/alertbox/video.html
Foremski"s take: It just shows how challenging it will be to repurpose content from one screen to another. We live in a three-screen world: TV, PC and pocket screen. Each one demands specific characteristics to be compelling, otherwise wandering eyes lead to wondering what else is on...