Vendor(0)shopper e-clothes e-travel e shopper s Figure I A suggested representation of a virtual e-commerce environment. Shopper-Vendor context is not discussed because of its simplicity Shopper-friend context Request for advice feature: the shopper asks her friend for a recommendation regarding the goods she would like to buy. If the shopper's friend returns a positive recommendation, the shopper pursues her purchase. Otherwise,the shopper may change her intention. When the shopper's friend does not pro- vide any recommendation, the final decision of pursuing or stopping the pur- chase goes back to the shopper. sh Compete feature: two shoppers are in competition for the same goods;the pper-Shopp er contex shopper who offers the highest price will get the goods. However, the final decision of selling goes back to the vendor who has to take into account hi interests. If the vendor accepts the offer of the first shopper, he has to reject better deal from a vendor. For instance, the shoppers decide to introducet a Cooperate feature: two shoppers are in cooperation and join efforts to unique order to ask for a discount and at the same time to share transporta- tion fees. Acting on behalf of both shoppers, one of them submits a purchase request to the vendor. The vendor either accepts or rejects the offer. Be interested in feature: the shopper is interested in the goods of another shop per. Therefore, she decides to get the same goods probably from the sam vendor as the other shopper. If the shopper is aware of the purchase condi tions under which the other shopper has obtained the goods, she may request the same conditions ese conditions meet her requirements Vendor -Vendor context Compete feature: two vendors are in competition for the goods to be vendor cuts the of his goods offered shopper accepts the offer of one of the vendors, she has to reject the offer of the other vendor and vice-versa 256 December 2003/oL.46. No. 12ve COMMUNICATIONS OF THE ACM• Shopper-Vendor context is not discussed because of its simplicity. • Shopper-Friend context – Request for advice feature: the shopper asks her friend for a recommendation regarding the goods she would like to buy. If the shopper’s friend returns a positive recommendation, the shopper pursues her purchase. Otherwise, the shopper may change her intention.When the shopper’s friend does not pro- vide any recommendation, the final decision of pursuing or stopping the pur￾chase goes back to the shopper. • Shopper-Shopper context – Compete feature: two shoppers are in competition for the same goods; the shopper who offers the highest price will get the goods. However, the final decision of selling goes back to the vendor who has to take into account his interests. If the vendor accepts the offer of the first shopper, he has to reject the offer of the second shopper and vice-versa. – Cooperate feature: two shoppers are in cooperation and join efforts to get a better deal from a vendor. For instance, the shoppers decide to introduce a unique order to ask for a discount and at the same time to share transporta￾tion fees. Acting on behalf of both shoppers, one of them submits a purchase request to the vendor. The vendor either accepts or rejects the offer. – Be interested in feature: the shopper is interested in the goods of another shop- per. Therefore, she decides to get the same goods probably from the same vendor as the other shopper. If the shopper is aware of the purchase condi￾tions under which the other shopper has obtained the goods, she may request the same conditions if these conditions meet her requirements. • Vendor-Vendor context – Compete feature: two vendors are in competition for the goods to be offered to the same shopper. For instance, a vendor cuts the prices of his goods. If the shopper accepts the offer of one of the vendors, she has to reject the offer of the other vendor and vice-versa. 256 December 2003/Vol. 46, No. 12ve COMMUNICATIONS OF THE ACM Figure 1. A suggested representation of a virtual e-commerce environment