It just a thought, but I used to post on this website www.b3ta.com/
They attach an icon on you postings for a week after you join that are bascily L-plates when you first start posting on there threads.
It can get very ruff in there as it is mostly populated by sarcastic teenage boys and has an unlimited bottom of bad taste.
Weirdly posters do give you a bit of a break in your first week as you get to know the netiquette of the place. And then kick the crap out of you verbally once your plates are off.
I recon MN could maybe do with something like this as it could make Troll identification a bit easer as well, if you have a doggy thread and L plate.
Could make this place a bit less daunting for newbes and maybe a little friendlier..