Let the hive mind of Engadget get that for you.
"I need help! I want a small pocket camcorder but I'm not sure which one to get. I don't want to fall into the hype of the Flip because I worry two hours won't be enough. What should I be looking for when considering a small camcorder and where can I get a good quality one with expandable memory? Thanks!"
Correct. Apparently the blu layer is composed of some sort of film that reflects the wavelength of a blu-ray laser, while permitting most of the dvd wavelength laser to pass through.