I have
this book, and it's infinitely useful to flip through and see which muscles are effected by which exercises. You probably already know the major ones, such as hamstrings in deadlifts, but in true deadlifts (not stiff legged or sumo), many more muscles are used. If you get a chance to browse the book in a store, check out page 83, and you'll see that deadlifts work most of your back, your hamstrings, your glutes AND your quads. Watching the video above, it makes since that conventional deadlifts would work your quads more, since you're bending your knees more. Anyway, double check your form of course, but realize that the deadlift is nearly a total-body exercise.