Levels 1-10 are basicaly how you can tell who you can and cant ski with.     
Like me, a level 9, i can ski in dynamic parallel (knees nad ankles locked together) on all double black diamond terrian, and navigate triple black diamond runs.   
A level 10 does the same, but on ALL terrian... these are your X-Games/Olympics guys/ladies.   
Level #   
1 Can navigate all green terrian. 
2 Can navigate all green terrian in DP. 
3 Can navigate all blue terrian. 
4 Can navigate all blue terrian in DP. 
5 Can navigate all SBD terrian. 
6 Can navigate all SBD terrian in DP. 
7 Can navigate all DBD terrian. 
8 Can navigate all DBD terrian in DP. 
9 Can navigate all TBD terrian. 
10 Can navigate all TBD terrian in DP.   
I saw this chart when i was at Vail.  At that time i was a level 7... after 2 more days in Colorado and a week in Whistler, 8 went by real quick, and i got stuck on 9.   
Unfortunatly, if you navigate Spanky's ladder (QBD), your called nothing but crazy.  That thing is so crazy.  35foot cliff to start off, then a 65 grade slope that about 200yrds (yea i was suckin air @ 18600ft), a flat, then another 40 grade with retarded amounts of mougles, boulders, and 10-15ft cliffs.   
It was a rush  smile.gif