A seller is anyone, individual or company, who posts an item on Bamsell to sell.
Why use Bamsell? Because your network will recommend your item to their network and earn cash for it.
A recommender is anyone who, even if he has nothing to sell, find seller's a buyer by recommending items to his network. Each sale generated gives you cash. The items he recommends will appear in his own shop.
Buyer on Bamsell will find the best deals as his network will recommend them for him.