1. the general public
1.1 can visit the Web site.
1.2 can subscribe.
1.3 item can be viewed on the site.
2. the members of the system.
2.1 can edit personal information.
2.2 personal data can be viewed.
2.3 can post comments about the item.
2.4 can give satisfaction score per item.
2.5 can be ordered.
2.6 can see a list of purchase order.