One of form of electronic commerce (EC). It is the transaction which is done between general consumer (consumer). As for transaction between enterprise B to B(Business to Business), enterprise and as for transaction of the general consumeryou call Bto C (Business to Consumer). Usually,on Internet it is actualized as auction, the system in order to do auction on the net and it offers "the place", the business which collects commission from the exhibition person has extended quickly. As for the enterprise which manages auction,independentgroup and Yahoo of the eBay corporationand the like!And so on there isa majorportal sight and the like. In addition, for the individual of liquidation and the physical distribution etc. for buying and selling between the individual after the auction being formed also the enterprise which offers service can C to C enterprise.