Years ago when I was first starting to learn stroking and edges, my instructor commented that with practice, I would eventually would get it, especially since I was blessed with soft knees. At the time, I didn't know what he meant exactly because I was too busy not giving myself a concussion. (I started skating seriously after college so with my first full-time job as a paralegal, I was nervous that somehow I would fall on my head and miss work!) Plus, the words "soft knee" didn't sound too good in general.
Now I realize what a great compliment it is when someone says I have soft knees. Back then, I kept my knees perpetually bent (and my back straight) because I thought that if I fell, the impact would not be so bad since I was already closer to the ground due to my knees being bent all the time. Little did I realize that my fear translated into having great knee bend while skating to this day. A skating friend tells me she loves to just watch me go around the rink because I look like I'm "floating, it's like buttah."
Having soft knees, or keeping the knees bent, is one of the cornerstones of skating, especially when landing jumps. Soft knees act as shock absorbers and make jumps and other elements look gentle, light, effortless, and quiet. To have soft knees also means that you have strong knees, so it's important to strengthen the muscles surrounding the knees (quadriceps and hamstrings) in order to be able to keep that nice knee bend while skating.
Nobunari Oda of Japan has the best soft knees of all the skaters. Here is a link to his short program at the 2006 World Championships in Calgary, Canada (he came in 4th overall). The commentators are all amazed by his knee action and focus a lot of their comments on how "divine," "wonderful," "light," "soft," and "excellent" his knees are. Only in skating can we be so effusive about the knee!