I saw this once and was immediately turned off by the videos. Not only is it harder to go to a specific place and look at things again, but as someone with hearing problems, videos without captions are an immediate deal-breaker for me. I really wish the web wouldn't turn toward video instead of written material; one of the reasons I've enjoyed the web so much is its focus on reading instead of listening.
+1. Plus the speed of reading is many times higher than the speed of speaking/listening. Also, videos often cause me to space out after a few seconds and do something else, thinking, "I'll listen in the background." This usually doesn't work.