On-line trading services in which seller posts products to be auctioned and bidding is done via the Internet, providing information about truck sales by means of the Internet, operating on-line marketplace for sellers of goods (used trucks), promoting the goods (used trucks) of other through on-line ordering and cataloging of those goods, providing an on-line computer database featuring trading information in the field of used truck inventory/sales, and providing on-line forums for transmission of messages among computer users concerning used truck inventory.