Seller and buyer rank
Seller rank and buyer rank, can be identified by two colored bars under each user avatar, on user profile page, next to user comments, etc.
Seller rank is a number from 0 to 100, the seller with 100% rank is the one user with most sales. 0% seller rank meaning that the user had no sales yet.
Buyer rank is a number from 0 to 100, a user with 100% buyer rank is the user that purchased most files.
A user with 0% buyer rank is a user that never added funds to purchase anything from the site yet. It is still a possible client.