Hey - saw the same advert on TV last night. Tyler (my son) asked me about it given LCD and Plasma are the big news items.
Just checked Wikipedia (because its ALWAYS 100% accurate, honest and believable

) and it says -
"LED TV stands for light emitting diode television. This is a term used by Samsung to describe their line of LCD (liquid crystal display) TVs that are enhanced with LED backlighting. The term LED TV is controversial and currently a war of words and advertisements is ongoing between Samsung and its competitors. The competitors' complaint is that the display is not comprised of 100 % LEDs and so should not be called LED TV. However, displays made entirely of LEDs are commonly called OLED TV and is a category of television that is not currently on the market. It could be fairly said that LED TV is a hybrid technology.
LED TVs are different from LCD TVs in 3 critical areas important to the consumer: 1- they have a crisper and brighter picture and produce deeper blacks. 2- they are extremely slim and lightweight and can be hung like a picture. 3- they use less electricity and do not use toxic mercury in their manufacture."