I guess it is a way to see, if someone is a spammer or a registered vendor here, who arn or the other gods did approve of. Cuts on "SPAM" reports I guess.
There's no approval system. You just have to fill in the vendor name and URL fields in your profile. It's only recommended for users that actually represent a company and help users.
As a representatives of a vendor business you may post about your company or products or services when the following 5 conditions apply:
You have made your vendor affiliation clear by filling in the Vendor Name and Vendor URL fields in your user profile and setting About Me to Everyone in your profile privacy options.
You are posting about Apple-related hardware, software, accessories, or services.
You represent, work for, or own a manufacturing, wholesale, distribution, or retail business (including software vendors).
You are replying to forum posts to answer questions when your product/service is particularly relevant to the question. Example: Your company or product was mentioned by name or your product suits a specific requirement being discussed.
The purpose of the post is to help forum members, not merely to benefit your organization.
Vendors must not use these privileges to
repeatedly mention their products in general discussion threads, even those about their market area
start threads to discuss, promote or advertise their business, products, or services
"badmouth" competing companies or products
use the forums to carry out business operations, e.g., solicit feedback, provide customer service, announce special deals, promos, or new products.