Company's multilingual Web site. In 2009, 33 percent of the bidders at Ritchie Bros. auctions bid over the Internet; online bidders purchased s830 million of equipment. Spot (or exchange) markets. On spot electronic markets, prices change by the minute ChemConnect.com is an online exchange for buyers and sellers of bulk chemicals such as benzene, and it's a B2B success in an arena littered with failed sites. First to market, it is now the biggest online exchange for chemical trading, with 1 million barrels traded daily. Customers such as Vanguard Petroleum Corp. in Houston conduct about 15 percent of their spot purchases and sales of natural gas liquids on ChemConnect's commodities trading site. Private exchanges. Hewlett-Packard, IBM, and Walmart operate private exchanges to link with specially invited groups of suppliers and partners over the Web. Barter markets. In barter markets, participants offer to trade goods or services. Buying alliances. Several companies buying the same goods can join together to form pur chasing consortia to gain deeper discounts on volume purchases. TopSource is an alliance of firms in the retail and wholesale food-related businesses.