Online transactions save time and money by eliminating paper forms, faxes, and phone calls, and by allowing buyers to compare prices quickly. Save time on research. Researching potential suppliers is faster and easier online, and it opens a global market of potential vendors because location is irrelevant on the Web. Shipping costs may be prohibitive, however. Pool purchasing power.
Many sites fall under the heading online exchanges.
Exchanges can be public or private. One of the advantages is that these exchanges are supposed to be neutral, not biased toward seller or buyer, although it's not unheard of for market makers to offer vendors equity in the exchange to tempt them to join. The best exchanges offer good customer service, helping buyers by offering product information and selection tools and ordering, billing, shipment, and scheduling services instead of just signing up companies and leaving them to fend for themselves. These exchanges also may offer the sellers help with introducing new products. A private exchange is owned by the company selling the goods.