Soo, here's some info about dlvling :)
It's the same as you lvl your character (kill mobs for XP), only backwards :P You put all your items to your wh and attack the town guards over and over and over again. The point of it is reaching a certain lwl that is below your current one, for example: You are a Bounty Hunter (spoiling dwarf) and you are spoiling a mob named Nos for coarse bone powder and it is about lvl 40. By killing it you gain XP and gain levels. Eventually Nos is out of your league - you gain no more drop and spoil, cause it's nick is now blue to you. You need cbp to make money, so you need to reach lvl 40 again. If a BH is you sub, you just cancel the one you have now and take a BH as your sub class again and you're lwl 40, but if a spoiler is your main char, then you need to delevel. I hope this explanation helps :)
There were people who reached lwl 78, took their last skills and started deleveling to lvl 4. At lvl 4, a passive skill Lucky takes effect. You lose no more XP and items while you're lvl 4 and you die. You don't lose your lvl 78 skills so you can go killing people and gaining Karma with no worry of losing anything, but the downside is that at lvl 4, all you can wear is no-grade equipment x)
P.S. Deleveling is just as hard as lvling, so sometimes dwarfs use a Sin Eater, to get rid of XP, cause they hate deleveling.