BN - Badly named
WN - Well named
VWN - Very well named, and so on
Tiers were created as part of trading on the PC to value pets against each other. It used to be hosted on /~Efflie and then /~Delvac (and some pages before those), but I'd have to go look for the current page it lives on since Mike/shatterell, the previous owner, disabled his account recently. Edit: it's /~Danpo
Hope that helps! People can give a lot of advice around here if you need it.