| 摘要 |
PROBLEM TO BE SOLVED: To enable a user to easily and continuously barter an article.SOLUTION: A server 10 is configured to: store article identification information of articles, user identification information of users possessing their respective articles, and state information indicating availability of the articles for barter, in association in storage means; receive a barter request from a user terminal 20A; in response to reception of the barter request, inquire of a user terminal 20B of a user possessing a barter target article whether to barter the target article; receive barter approval information from the user terminal 20B; in response to reception of the barter approval information, change the setting for the article of which barter is concluded from the stored user identification information to the user identification information of the user after the barter; and according to the new setting of user identification information after the barter, set the state information of the article after the barter to be a barter available state. |
